None
None
Ifos nruikuo 'siaauiipos a»mo 2 i c I £ o "? »- gsss;ss;;§^ § 8 s 5 ©1 §"' q: s 8 5 8 8 3 ^ «- o •o •o eo s S « n < m c s S o o ~C ~^^ ~f' S~ ~^~~ « s 2 oi s oa s 3 s 3 S S S o i5 < as w ^ p-l 8 iO « n 5 s s B ^ ^ 8 ^ ^ 8 8 s; -< g £; g g ao ^ 8 ^ s S 2 s g^ § 5 ^ 04 ©» •"• 8 o IO n S ^ ■-W IT g ;:; "r ;; "s" "r o ^ " r- G* •-I r^ -^ ^ g -< ^- s s SS 2 CD 8 (P n r^ S S g •* n « ■^ -* « § g o n g t^ g B ^ "8" 8 & 3 o 1? ? o ■* r- -^ ec -^ s o -< s o 5 o § S g f5 o 00 8 8 00 ss ^ •o ss f^ _^ p-l 00 00 OS 8 {2 •* 1° .a « - 2 5 I 5 c o o o •^ CO ^ (» * « X S X c O SOS o <1 -3 S o "^ a 'Z o ^ 2 "E « s t S PU CA > :2 * ^j3 *^ .2 (/: » © O "3 6 i- 5 ^ en ^iP 03 It appears from these analyses that the "clay "is by far the richest in mineral ingredients, the amount being more than twice that of the others combined. Its insoluble residue is very small, while the soluble portion consists largely of free silica derived from h3drous silicates of the bases. Its volatile matter (which includes hygroscopic moisture left after drying at 100° C, and water of hydration) is of course tlie largest ; as are also the remaining ingredients, except lime. The A. A. A. 8., VOL. XXn. 6 Digitized by VjOOQIC 82 A. UATHEMATICS, PHT8I08 AND CHEMIBTRT. large amount of soda, however, is due to the chloride used in the precipitation of the diffused clay. In the other sediments, the soluble ingredients, except soda and lime, decrease in almost a geometrical ratio ; there being also a corresponding increase of sand. There are several interesting points in connection with this ra- tio of decrease which may be summed up as follows. 1. The iron and alumina exist in almost identical relative pro- portions in each sediment; making it probable that they are in some way definitely correlated. , 2. Potash and magnesia also exist in almost the same quan- tities, and their ratio to each other in all the sediments being al- most constant seems to indicate that the}' occur combined, perhaps in some zeolitic silicate, which may be a source of supply to plants. 8. Manganese exists only in the clay, a mere trace being found in the next sediment. 4. The lime appears to be " nowhere " having probably been largely dissolved, in the shape of carbonate, by the large quantity of water used in elutriation. Its increase in the coarser portions may be owing to its existence in the crystallized form, not so readibly soluble. In a general summation of the ingredients in the several sedi- ments and comparison with the analysis of the soil per se^ there is a loss in potash, magnesia and lime ; which may reasonably \)e supposed to have been dissolved by the water of elutriation. Some of the soluble silica clearly remains undetermined in the coarser sediments. The differences in ferric oxid and alumina, shown throughout the analyses of this soil, may partly be accounted for by the une- qual distribution of the particles of iron ore existing in the soil. Of course the law of distribution of soil ingredients may differ in other soils ; but the great distance from the point of derivation of the materials, and the wide distribution of the soils of which this is a type, probably render the above results of more than local applicability. Digitized by VjOOQIC A. MATHEMATICS, PHTSIC8 AMD CHEMISTRY. 83 On THE Influence of Strength of Acid and Time of Digestion IN THE EXTRACTION OF SoiLS. By R. H. LoCGH RIDGE, Of Oxford, Miss. The following investigation was andertaken with a view of de- termining the extent to which the variations, liitely to occur in the extraction of soils by hydrochloric acid for the purpose of analysis, can influence the ultimate results ; the special object being to ascertain the comparability of the analyses made in connection with the Agricultural Survey of Mississippi, both among themselves, and with those made by similar methods by Dr. Peter, of soils collected by the Surveys ' of Kentucky and Arkansas. In beginning the analyses of Mississippi soils in 1858, Dr. Hilgard adopted the following method, which has also been adhered to by his successors in this work, in over two hundred analj'ses made. The soil (i. e., "fine earth") is pulverized with a wooden pestle and thoroughly mixed. The hygroscopic moisture is determined, after exposing it in a space saturated with vapor, in a layer not exceeding 1°™ in thickness, for twelve hours, by drying at 200° C. in a paraffine bath. Of this dried substance from two to three grams are usually used in the general analysis, the methods em- ployed being in general those adopted by Dr. Peter. ^ In another portion, after ignition, the phosphoric acid is determined by diges- tion for five days with nitric acid at 100° C, evaporation, pre- cipitation by ammonium molybdate, digestion at 100°, solution in ammonia and precipitation by magnesium sulphate. For general analysis the soil is digested in hydrochloric acid of strength 1'115 (as a rule) at 100°. It is then evaporated to complete dryness, this adding another day to the digestion. In the insoluble residue the soluble silica is determined by boiling with sodic carbonate. The alumina and ferric oxid are precipitated according to Rose's method of boiling, for the com- plete separation of manganese, magnesium and calcium. The mixed precipitate is treated with potassic hydrate. After precipitation of the lime by ammonic oxalate, the am- moniacal salts are destroyed by Lawrence Smith's method, with aqua regia ; and the residue converted into nitrates, from which *Ky. Report, Vol. iii. Digitized by VjOOQIC 84 A. MATHEMATICS, PBTSIC8 AND CBBMISTRT. sulphuric acid is precipitated by barium nitrate. The alkalies are then sepnrated by treatment with oxalic acid, ignition and wash- ing. In the residue, barium, manganese and magnesia are sepa- rated as usual. With the aid of a Bunsen's filtering apparatus we can, by this method, complete an analysis in five days exclusive of digestion ; and three analyses may be in progress at the same time. The substance experimented upon was a subsoil, a typical rep- resentative of the best yellow loam uplands of Mississippi, from the table lands of Benton Co., Miss. ; No. 219 of the Survey Col- lection.3 To determine the question as to whether such variations in the strength of the acid, as might possibly have occurred in the use of the steam distilled (i. e., from a retort surrounded by steam) product, without previouslj' ascertaining its concentration, portions of the subsoil were digested five days with hydrochloric acid of the strength, severally, of 1-100, 1115 (the normal concentration) and M60. As to the time during which the soil must be digested in hy- drochloric acid that the (sensible) limit of its solvent action upon the important soil ingredients may be reached. Dr. Peter's prac- tice has been to digest for about ten days, in his 800 analyses of Kentucky and Arkansas soils ; while, for reasons of convenience, half that time has been adopted in the analyses of the Mississippi Survey. The question whether under these circumstances, the two series can be deemed comparable, was approached by diges- tions for periods of one, three, lour, five and ten days, of the same soil with the same large excess of acid of 1*115; all precautions being taken to accomplish each analysis as nearl}- as possible under the same circumstances. For the digestions, use was made of porcelain beakers (the use of glass being objectionable because of its solubility) ; the same amounts (40''*'™) of acid were used, and steam kept up about twelve hours each day. The hour of ^'putting down" was carefully noted, and at the end of the allotted time the solution was poured off from the in- soluble residue, and each evaporated to dryness separately and reunited in solution, to prevent any further action of the acid. *The analysis of the subsoil of a neighboring tract is given in Hilgard's Report, 1860, p. 2SI2. Digitized by VjOOQIC A. MATHEMATICS, FHT8IGS AND GHBMISTRT. 85 The results of the investigation as to strength of acid are as follows : — 8P O. OF ACID. INGRBDIE^TS 1.10 1.115 1.160 Insoluble Residue . .. 71.88 70.53 74.15 Soluble Silica .... 11.38 12.30 9.42 Potash .60 .63 .48 Soda .13 .09 .35 Lime .27 .27 .28 Mngrnesia .45 .45 .45 Br. Ox. Manganese . .. .06 .06 .06 Ferric Oxid 6.16 5.11 5.04 Alumina 6.84 8.09 6.23 Sulphuric Acid .... .02 .02 .02 Tolatile Matter .... 3.14 3.14 3.14 100.02 100.09 99.29 A mt. of Soluble Mn iter. 24.00 27.02 22.27 Amt. of Soluble Bases .. 13.60 14.70 12.83 It thus appears that in the strongest acid the amount of insol- uble residue is far greater than in either of the others, and that the difference lies chiefly in the soluble silica and alumina (i. e., clay), together with potash and lime. The other ingredients seem to be indifferent as to the strength of the acid. Between the acids of strength 1-10 and 1-115 the difference is not so great, but the advantage is clearly with the latter, the amounts of silica, potash and alumina being greater, while the lime remains the same in both. This result points to the conclusion, that while lime and mag- nesia (being readily dissolved) are probably present chiefly' as carbonates or hydrocarbon ates ; potash as well as alumina, and to some extent lime, are present as silicates, and for that reason are not as fully extracted by acid of low strength as by that of 1-115; although the former acts more powerfully than that of M60. The latter fact (the coincident result of two analyses), though Digitized by VjOOQIC 86 A. MATHEMATICS, PHYSICS AMD CHEKI8TRT. unlocked for, is not without analogies, although its precise cause, in this case, still requires elucidatiou. Whether the maximum of action is exerted by acid of 1*115 is another question of some interest, to be determined hereafter. As for the comparability of tlie analyses as affected by the prob- able variations of strength of acid, I remark that the acid used for distillation by Dr. Peter, as Dr. Hilgard informs me, was the "C. P." of commerce, whose strength rarely much exceeds or falls below that of 1*115 ; while that used by us was usually the crude, diluted nearly to the same strength. The first and last portions coming over were habitually, 1 believe, rejected in either labora- tory'. Under these-circumstances, it is very improbable that either of the extremes of sp. gr., above discussed, ever actually oc- curred; especially as regards the strongcr^acid, which being in small quantity, would always be mixed with the succeeding weaker distillates. It is therefore not probable that the percentage of potash or other important ingredients, could have been so far underestimated in either of the series of analyses, as seriously to influence their com- parability, either within themselves, or with each other. The experiments on the influence of the time of digestion, made with acid of 1*115, resulted as shown in the table opposite. It appears that the amount of dissolved ingredients increases up to the fifth day, the increase becoming, however, ver}' slow as that limit is approached. It is also found that the ingredients offering the greatest resistance to this action are the same as those whose amounts were sensibly affected by the strength of acid, viz., silica, potash and alumina.^ In regard to lime and magnesia, one day's digestion not being 8ufl3eient for full extraction, it is evident that they do not exist in the soil as carbonates or hj'dric oxides only, as has been supposed ; but also as silicates. A comparison of the results of the five and ten day digestions shows that the solvent action of the acid has substantially ceased there being no further increase of the amount of dissolved matter. 1 There Is an apparent loss of alumina in tbcfour days' digestion, owing to the laclc of a second Beparation ft-om iron, whose quantity is correspondingly increased. Digitized by VjOOQIC MATHEMATICS, PHYSICS AND CHEMISTRY. 87 So far, therefore, as the time of digestion is concerned, the anal- yses of the Mississippi Survey are strictly comparable with those of Arkansas and Kentack}^ soils, made by Dr. Peter.- INGREDIBKT8. 1 No. OF Days Diqbsted. 3 4 6 10 iDsolable Residae . .. 78.97 7-2.66 71.86 70.63 71.79 Soluble SiUoa 8.60 11.18 11.64 13.80 10.96 Potash .36 .44 .67 .63 .62 Soda .06 .06 .03 .09 .28 Lime .26 .29 .28 .27 .27 Magnesia .43 .44 .47 .45 .44 Br. Ox. Manganeae .. .04 .06 .06 .06 .06 Ferric Ozid 4.77 6.01 6.43 6.11 4.86 AlomiDa ...... 5.15 7.38 7.07 7.88 7.16 Phosphorio Acid . .. .21 .21 Sulphuric Acid . . .. .03 .02 .02 .02 .02 Volatile Matter .... 3.14 8.14 3.14 3.14 3.14 TOTAL 89.68 100.68 100.66 100.69 99.80 Amount of Soluble Matter 15).67 24.88 26.57 27.02 24.87 " ■< *' Bases. 11.05 13.68 13.91 14.49 13.68 Digitized by VjOOQIC 88 ▲. MATHEMATICS, FHT8ICS AND GHEMISTBT. Remarks on Glass-making. By Lewis Fkdcbtwanger, of New York, N. Y. Considering the incalculable benefits which the discovery of glass has rendered to mankind, not alone for purposes of daily life as an article of domestic use, but, I may say, for more important and higher objects, as by the knowledge of glass and its applica- tions tlie most accurate observations and experiments in astronomy, natural philosophy, chemistry and physiology have been performed, we have nevertheless been very slow in keeping pace with the dis- ' coveries and improvements in other kindred arts and sciences. While Pliny and Strabo gave at an early period very accurate ac- counts of the glass manufacture in Alexandria and even the Port- land vase, which was the most beautiful specimen of colored antique glass and was found in a marble sarcophagus, within the tomb of Alexander Severus, who died in the year 235 ; we have only the full description of the art of glass-making from Agricola in 1550, and have the information of the first glass-house in England in the year 1557 and that in Sweden in 1641 ; still very few improve- ments have been brought to light, — the same furnaces, the same tools, the same materials and the same glory-hole have been to this day retained these 320 years : if we except the application of Siemens* Furnaces, which are intended to save the heat of the gas, which is not taken up In the reduction of the glass materials, while the chamber under each end of the furnace is so arranged that the outer one receives the air and the middle one mixes and ignites air and gas, whereb}' the heat is saved at a very great per- centage so as to calculate one pound of glass from one pound of coal. The discovery of LeBlanc in 1792, which is the conversion of common salt into carbonate of soda, is another improvement of the eighteenth century. The application of glass for optical pur- poses such as microscopes, telescopes, cameras, etc., has for fifty years past occupied the unceasing attention of the greatest phil- osophers of the nineteenth century without fuUj' overcoming the many obstacles ; it arises from the power which glass possesses of refracting light or turning it aside from its original direction ; the property of decomposing white light and giving rise to colors ; for an instrument constructed with lead glass lenses will produce an Digitized by VjOOQIC A. HATHEIIATICS, PHTSICS AMD CHEMISTRY. 89 image of the heavenlj^ bodies or of microscopic objects with a colored margin, which will preclude the possibilit}' of accurate observation. The experiments of Faradaj', Frauenhofer, Utzschneider, Guinand and Bontcmps have been met with many difficulties in producing an achromatic lens, for tlie simple reason that the refractory power depends upon the different density of materials, and a want of uni- formity in the refractive power of the glass in different parts of the mass, and whenever a denser layer of glass comes in contact with one of less dense matter a streak is produced which will occasion distorted images. In 1827, while a student in Jena, I assisted my teacher, Koerner, in numerous experiments of glass-making, principally for obtaining achromatic glass of uniform density, by the use of caustic baryta, borax, and silex, all materials very carefully prepared for the fur- nace, keeping the mixture in fusion for six days and allowing it to cool slowly for six days more before removing the pot, and then to break the same so as to use the lowest part of the mass for cutting up into lenses ; we succeeded but partially. Faraday's report in 1830 speaks of his borosilicate of lead which yielded him a heavy glass of 5*4 specific gravity with a low dispersive power ; still it did not prove useful for optical purposes and was altogether unfit for the desired object. In order to obtain an achromatic glass of a fair standard, the manufacturers have of late years resorted to the expedient of com- bining one kind of glass, which is called crown glass, and composed of silex, potash and lime, with another glass called fiint glass, which contains an addition of sixty per cent, of oxide of lead, a combi- nation which would be satisfactory as regards the refracting power, but the difference of specific gravity through the whole mass has again produced the obstacle ; this had to be overcome by uniting numerous and small selected masses of glass of well ascertained gravity which must be quite uniform, into one large mass, while still plastic by pressure. It is clearly shown that fiint glass decom- poses light more distinctly, as regards the refracting power, than crown glass, which contains no lead ; and by employing a concave lens of lead glass and a convex lens of crown glass, when combined their respective effects upon light will compensate each other in consequence of the forces of the compound lens. Now all these remarks prove how deficient the art of glass-making is to this day, both in the production of achromatic glass as well as Digitized by VjOOQIC 90 A. MATHEMATICS, PHT8ICS AND CHBMI8TBT. in that of a proper and aniform composition. Tlie glass-maker has not yet appreciated the atomic theory, which would teach him that certain equivalents are necessary for the production of uniform mass ; he is behind the art of steel manufacture, for which the spec- trum gives him the sign when his ingredients are chemically com- bined. Dbsoription op a Printing Thbrmombter. By G. W. Hough, of Albany, New York. During the past quarter of a century numerous mechanisms have been constructed for recording automatically the fluctuations of temperature. The machines heretofore used for this purpose may be divided into three classes : — First, — Records made by a metallic thermometer by using either a single wire or a combination of rods. Second, — The application of photography, by means of which the height of the mercury in the thermometer tube is photographed in the form of a continuous curve. Third, — Records made at definite intervals from a mercury ther- mometer by the use of electro-magnetism. The first method is capable of giving approximate results. There are, however, serious objections to its use, the most important of which is the impossibility of making a piece of metal subjected to any work maintain its zero of length. To illustrate : — if a rod of brass or steel be made to support a weight, viz., ten pounds and at the same time be subjected to heat and cold, for a short time, the length of the bar at a given temperature will not be the same as previous to the experiment ; consequently, metallic thermometers will not maintain a fixed zero, — a fact observed by many meteorol- ogists. Another objection to the method of mechanical registration is that when a macliine is made to do work, its indications are not al- ways the same. The force required to make a legible mark seri- ously interferes with the accuracy of its results. Of the second method, by means of photography, it may only Digitized by VjOOQIC A. MATHEMATICS, PHT8ICS AND CHKMISTRT. 91 be necessary to state that the amoant of attention required in the preparation of the paper, the developing of the photographs and the measuring up of the records, preclude the possibility of its general use by meteorologists^ The records also are often indis* tinct, and the curve is never sharp, showing that all minute flue, tnations are lost. Of the third form of instruments, when the record is made at definite intervals by means of electro-magnetism, the zero of the thermometer, if of mercury, will remain fixed and the records will be correct within certain determinate limits. The only objection is, that changes occurring between the intervals of recording are not shown : with this exception, the method may be regarded for general use as superior to those before mentioned. A thermom- eter constructed on this plan has been in operation at the Dudley Observatory for the past three years. But the labor required for converting the curve into numerical results was so great, that it was decided to construct a machine that would give the height of the thermometer hourly, printed with type. The thermometer which we have adopted consists of a glass tube bent in the form of a siphon, the closed leg of which is filled with alcohol and the open one with mercury. On the surface of the mercury in the open end, there rests an ivoiy float suspended from a delicate balance, having platinum wires attached to each end of the lever ; when the column of mercury in the thermometer tube rises or falls from the eflfect of temperature, the platinum wires dip in small mercury cups placed underneath them, thereby causing a current of electricity to pass through one of two electro-magnets operating mechanism for giving motion to a fine micrometer screw. The motion of this screw elevates or lowers the carriage supporting the balance, thereby breaking the circuit. Whenever a change of temperature equal to one-tenth of a de- gree Fahrenheit occurs, the magnetic circuit is completed and the screw is moved a space equivalent to the change in the height of the mercury in the thermometer. By this method, which is the same in principle as our printing barometer described in 1866, no work is required to be done bj^ the thermometer, with the excep- tion of supporting one-half the weight of the float. The force re- quired to establish a magnetic current does not exceed two grains, and when once established even this pressure on the mercury col- umn is removed. Digitized by VjOOQIC 92 A. MATHEMATICS, PHYSICS AND CHEMISTRY. When the temperature rises or falls the screw follows its motion, at the same time the clock-work moves the type wheels, indicating the temperature, which is printed at the end of each hour on a slip of paper moving in front of them. A pencil held against a revolv- ing drum also records a continuous curve, exhibiting at a glance the height of the thermometer. The machine gives the temperature to tenths of degrees ; the probable error of an impression being about two-tenths of a degree Fahrenheit. The clock-work and printing mechanism are placed inside the building ; the thermometer and carriage only being out- side. The connection between them is made by a fine wire running over two pulleys and attached to the micrometer screw and balance. Description of an Automatic Registering and Printing Evap- orator AND Rain Gauge. By G. W. Hough, of Albany-, New York. One of the most important elements in the study of meteoro- logical phenomena has heretofore been too much neglected. We refer to the evaporation continually taking place on tlie earth's surface. But comparatively few observations have been made to determine the amount of water evaporated at different places and for differ- ent conditions of the surface. Engineers, in estimating the water supply for cities, have, until perhaps quite recently, -based their estimates entirely on the amount of rainfall, a very fallacious method, since it will be apparent to any one, on reflection, that for two localities of equal area and similar surface, the one covered with forest and the other exposing the ground uncovered, the amount of water which can be utilized will be much greater in the former case than in the latter. What ought to be ascertained, therefore, with the greatest precision possible, is the amount of the evaporation in forests and in the open country, as well as for different conditions of the soil. Although the rainfall has not sensibly changed in amount since the first settlement of this continent, yet it is well known that the Digitized by VjOOQIC A. MATHEMATICS, PHTSICS AND CHEMISTRY. 98 Tolnme of water in the brooks and small streams bas greatly di- minished. One need only make a journey through the older states and notice the ruins of former mills to be forcibly reminded of the fact. We recall to mind a number of instances of brooks, which in our lx>yhood were considerable streams for the whole season, and are now entirely dry during the greater part of the year. The amount of water annually reaching the ocean through our great rivers may not have sensibly diminished, yet owing to the gradual removal of the forests they become more and more subject to excessive fluctuations in volume, owing to the ease with which the rain-water, falling on an uncovered surface, reaches their chan- nels. The agricultural condition of the country, too, depends largely on the amount of evaporation. A record of the rainfall alone is not sufficient to determine whether the conditions for agriculture were favorable or otherwise. It is only when the two elements, rainfall and evaporation, are considered together, that correct con- clusions can be reached. The importance of the subject led us to devise a mechanism for recording continuously, in the form of a curve, the amount of rain- fall and evaporation, and for printing hourly, to the one five-hun- dredth of an inch, the same quantities. The discussion of such records would enable us to determine the diurnal variation of these elements, heretofore but approximately known. In order to record the fall of snow, and the evaporation from snow or ice in the winter season, without changing the apparatus or mode of registration, it was decided to record by weight instead of vol- ume, as is usually the practice. The apparatus consists of a vessel two feet square and one foot deep, suspended by means of one or more levers, and held in equi- librium by a small spriug balance. The amount of change in weight of the mass, either that due to the precipitation or evaporation, will then be indicated on the balance. It is obvious therefore, that were a pencil connected with the end of the weighing lever, it would trace, on a suitable revolving drum, the changes of weight. But such a crude device would not give results sufficiently accurate for ascertaining the hourly evaporation. If, however, in place of making the apparatus do mechanical work directly, the lever is made to vibrate between two platinum points, Digitized by VjOOQIC 94 A. MATHEMATICS, PHT8ICS AND CHEMISTRY. whenever a change equivalent to the weight of one five-hundredth of an inch of water takes place, it will touch one of the points, thereby establishing a circuit through one of two electro-magnets, operating a micrometer screw ; since the force required to complete an electrical circuit between two plates of platinum amounts to only a few grains, it is seen that no sensible amount of work is re- quired of the apparatus. This mechanism is now in process of construction. When com- pleted, the vessel for holding the water will be placed on the roof of the Physical Observatory with the recording apparatus inside ; the connection between the two being secured by means of a small wire cord. It will be exposed directly to the sun and wind, and will give results from which maybe determined the coefficients of temperature, wind, moisture, etc., affecting the rate of evaporation. The amount of evaporation from soil can be ascertained by filling a suitable vessel with soil saturated with water, and recording the weight either continuously or at definite intervals. On the Intuodoction of the Metric System into Medicine and THE Unification of Doses. By Harvey W. Wiley, of Indianapolis, Indiana. In Chemistry, the basis of pharmacy, the work of introducing the Metric System is accomplished. The first step, therefore, is already taken, affording a stronger reason for the completion of the work. There is certainly no great propriety in buying a kilogram of potassic bromide, and then dealing it out to our patients in grains and drachms. But because our physicians and druggists are used to grains and minims, drachms and fluid ounces, these values must be used as aids to something better. For practical purposes we may take the gram as equal to 15*5 grains. It is easy thus to change grain or multiple grain doses into tlie metric scale. Thus - 1 gram is equal to a grain and a half, so that those medi- cines which are now given in from one to two grain doses might read- ily be prescribed in doses of *1 gram. Digitized by VjOOQIC A. MATHEMATICS, PHT8IG3 AND OHEMISTRT. 95 Continuing the comparison, we find : — 8 grains 4-5 " = *2 gram = -8 " 6 _ .4. » 7-5 = -5 " 9 = -6 " 10-5 _ .7 » 12 = -8 " 13-5 = -9 " 15 r= 1 " r nearly. Of course these are only given as approximate values, and they will aid us in estimating how many grams, or what part of a gram of any medicine, should be administered, by a knowledge of the number of grains which we have been in the habit of exhibiting. After we have become familiar with the gram quantities, we need no longer think of the grains ; just as one who has a thorough knowledge of a foreign language does not translate it into his ver- nacular when rending. In regard to those medicines which are administered in a liquid form, we can make similar comparisons, subject to similar expla- nations. Thus 16*2318 minims = 1 cubic centimetre, or 1 milli- litre. Practically therefore : — 4 Minims = -25 Centimetres 8 = -5 12 = -75 15 = 1 20 = 1-25 24 = 1-5 28 = 1-75 32 = 2 " = half a teaspoonftil 36 (t = 2-25 40 (( =:2o 44 (C = 2-75 48 C( = 3 52 (i = 3-25 56 (( = 3-5 60 u = 3-75 64 44 = 4 " = teaspoonful = flui drachm nearly = 60 drops. Digitized by VjOOQIC 96 A. UATHEHATICS, PHYSICS AND CHEMISTRY. Let it be remembered » however, that the drop is as variable as the old system of measures ; for while about 50 drops of dilute sulphuric acid are equal to 4cra3, it requires 120 of laudanum and 150 of ether to make the same amount. But the size of the drop depends also upon the shape and size of the orifice through which it comes. These tables of comparisons might be continued to exhibit lar- ger or smaller quantities ; but, just as the}' are, they apply to the greater number of medicines administered. If it be objected that druggists would not know how to fill a prescription in which grams and cm^s were employed, it is suflScient to say that they could easily learn ; and any intelligent plu'sician or apothecary in half an hour could thoroughly master the Metric System and begin to write and fill prescriptions in its symbols to his almost unlimited advantage. I have, however, as the principal object of this paper and the especial purpose for which its preparation was attempted, to sub- mit a further suggestion to the profession touching the introduc- tion of the Metric System in medicine. It is a plan for the Unification of Doses, Every practising physician is painfully aware of the fact that mistakes are daily made in the compounding and division of med- icines which frequentl}' end in most diastrous results, and, unless the physician himself has an extraordinary memory, it is most difficult for him to keep in mind the proper amount, of any but common remedies, which ought to be administered. Especially' is this true of young ph3'sicians where the memoiy is not fortified by long experience. The young physician maj' ea- sily' make out his diagnosis and recall the remedy which is most appropriate, but among the thousand different quantities which constitute a dose, he cannot recall that one which belongs to the remedy he wishes to use. lie, therefore, either has to postpone its exhibition or guess at the quantity to be given ; in either case at a great risk. Moreover, every medical student knows that by far the most difficult part of the Materia Medica is that which re- lates to quantity'. lie can remember the source of the drug, the method of its preparation, its therapeutic action, its compatibles and incompatibles ; but when he comes to the proper amount for a dose, his memory fails him at the very point where practically he needs it most. It therefore seems evident, that if any system can Digitized by CfOOglC A. MATHEMATIOS, PHTSICS AND CHBMISTRT. 97 be devised by which the great majority of remedies in common use could be made to have a common quantity for a dose, the physician, the apothecary and the patient would all be benefited. In order that this happy pharmaceutical millennium may be brought about, it is necessary in the first place to establish at least two standard doses, one for solids and one for liquids. This being done, in the second place it will be necessary to have all solid substances so prepared that the standard dose will be the average dose of that solid for the adult patient. In like manner the liquid medicine should be prepared so that the standard dose would as before be the average for the adult pa- tient. Let us now fix these standard doses as follows. (This is only a suggestion in regard to the standard doses ; it could be fixed at any other value if found more convenient. It, however, fully illus- trates the principle.) For a solid let the standard be -2 gram. This is about 3 grains. Let quinine be taken as the typical solid. It is a normal solid. By this is meant that the standard dose, *2 gram, is the average dose for the adult patient. A prescription for quinine would therefore read H QuinisB sulphatis, grams ij (N). Sig. one every two hours till cinchonisra is produced. (N) signifies that the solid is normal^ i. e., the dose is -2 gram or three grains. This signifies that the apothecary is to put the two grams up in '2 gram powders. Therefore it is not necessary to rewrite it on the prescription. Suppose however the physician should desire to prescribe powdered opium. In this case of course the standard dose would be too large. It would be rather unsafe practice to exhibit *2 gram opium to a patient unaccus- tomed to its use. In order to meet this, and similar difflculties in solids and liquids, all manufacturing chemists should be required by law to make only standard mixtures and solutions or some multiple of the standard. Thus powdered opium thoroughly rubbed up with three times its weight of milk sugar, chalk or some other comparatively inert substance would become a normal mixt- ure and should be put up in a bottle labelled (N). The physician would therefore write. H Opii pulveris gram j (N). Sig. one at night before bedtime (etc.). Morphia on the other hand should be most thoroughly trvki- A. A. A. 8. VOL. XXII. 7 Digitized by VjOOQIC 98 A. IfATHEMATICS, PBY8IC8 AND CHEHISTRT. rated with seventeen times its weight of equal parts of milk sugar and challc, in order to form a normal mixture; we could then write R Morphias snlphatis, gram, ij (N). Sig. one every two hours till h^'pnotic effects are secured. In such cases as these, the salt perhaps would be better made into a normal pill weighing -2 gram. All pills can thus be readily reduced to the standard by proportionate variations in their in- gredients. In like manner it would be exceedingly easy in the decimal sys- tem to make all mixtures of solids in such proportions as would give the leading ingredients the average dose in the standard dose. The case of the compound cathartic pills will illustrate the whole series. Thus these pills made according to the following recipe contain precisely the same proportion of compound extract of colocynth, calomel, jalap and gamboge, as the pill formed according to the formula given in the " U. S. Dispensatory," but each pill will of course be standard, i. e., contain -2 gram which is a very little less than the ordinary pill. R Comp. ext. colocynth, grams xij. Ext. jalap. Calomel, ai grams jx. Gamboge, grams ij. Mix, make 160 pills. This would give pills of the standard weight, and one of these would be an ordinary dose for a mild laxative. Thus we see that by means of the metric sj'Stem, all prescriptions for solids may easily be made to conform to the standard dose; a thing which would be almost impossible under the present system of weights. Again, all substances which are given without mixture may be made normal, in fact can easily be made so. In case, however, the substance is of such a nature that the standard dose is not sufficient to produce the required effect, it should be so mixed that two, or three, or four, times the standard dose would be the average dose for the adult patient. It should then be labelled (J N) (J N) (^N) etc., signifying that the dose is twice, three times, four times, etc., etc., the standard. On the other hand, should it be inconvenient to dilute the very active solids, such as morphia, to the normal, let the dilution be in Digitized by VjOOQIC A. MATHEMATICS, PHT8ICS, AND CHEMISTRY. 99 some maltiple of the normal and labelled (2N) (3N) (4N), etc., signifying in each case that the dose is one-half, one- third, oue- fourlh the standard. But this is, I hope, suflScient to present at least the outlines of the proposed plan of unification as far at it applies to solids. Let us now consider the same problem in liquid medicines. It would be well to refer here to the table of comparison between minims and cubic centimetres. From this it appears that the most convenient standard dose of a liquid is 4cm.^ equivalent to 64 minims nearly, or one fluid drachm, or a teaspoonful. Let us take this then as a standard dose. The bottles in which medicines are given out could be furnished with glass stoppers hollowed out with a cup-shaped cavity measured to hold 4cm. ^ Teaspoons are so variable in size that they are not always to be depended on to measure a dose. Of course as in the case of solids the manufac- turing chemist should be required by law to put up only standard solutions or some multiple of that standard. Nothing would be more easy than this and it is but right that the profession should be protected from the cupidity of manufac- turers which leads them often to dilute ofl9cinal preparations. The government should appoint an inspector who should see that every liquid medicine exposed for sale is normal, i. e., that a dose of 4cm.3 contains the average dose of the active principle in the liquid for the adult patient. In the case of laudanum, for instance, it is well known that when the crude opium is high the tincture is weak so that the physician is safe in prescribing twice as many drops when opium is twenty dollars per pound as he does when it is ten. Let us suppose, however, that we have some laudanum of ordinary strength of which 16 minims contain one grain of opium. How now are we to standardize this solution in order to apply the principle of unification ? The standard dose which we have assumed is 4cm.3 or about 64 minims. Hence if we dilute the laudanum with four times its bulk of water or mint water the solu- tion becomes normal and then we may write R Tine, opii 1 decilitre (lOOcm.3) (N). Sig. 4cm.^ (a teaspoonful) before bedtime or until soporific effects are produced. Here 4cm.3 represents 1 grain of the crude opium or nearly so. Again, the common ofiScinal aromatic dilute sulphuric acid, diluted Digitized by VjOOQIC 100 A. MATHEMATICS, PHTSIC8 AHD CHEMISTRY. with six times its bulk of water or mint water, becomes normal and we write R Siilph. acid dil. aromat. decilitre j (N). Sig. dose every three hours. (N) signifies alwaj's that Aem^ is tlie dose for the adult patient. Should it be desirable to administer quinine with the above acid the prescription can be varied thus : R Aromat. sulph. acid, decilitre j (N), Quinise sulphatis, grams v. Mix. Sig. dose every two hours until cinchonism is produced. Since the five grains of quinine dissolved in the acid would not in- crease its bulk appreciably, this increase is practically neglected (1 decilitre is 3^ fluid ounces nearly). Again, the ordinary dilate phosphoric acid by the addition of one-half its bulk of water or mint water becomes normal and, as before, we write H: Phos. acid, dil. decilitre j (N). Sig. every four hours. Or if it be desirable to give strychnia in the phosphoric acid, H Phos. acid, dil, decilitre j (N), Strychnia, -04 grm.. Mix. Sig. every four hours. • VVc thus administer about yfjj gr. strychnine at each dose, etc. It is not worth while to multiply examples. I hope that I have made my idea clear ; that at least this paper may direct the mind of the profession to the merits of the metric system which is certain sooner or later to reform the nomenclature of remedial quantities. If it be urged in objection to the foregoing suggestions that there would be great difficulty in making and keeping these normal so- lutions, it will be sufficient in reply to call attention to the fact of their very general introduction into the science of quantitative chem- ical analysis within the last few years. The analyst has found his work greatly lessened and calculations simplified by their use. I can safely affirm that every practical analyst who has ever made use of these normal solutions will cheerfull}' bear witness to the beauty and simplicity of the modes of analysis into which they enter. With a burette, a pipette and litre flask it is possible to make analyses which would require by the gravimetric method extensive and costly apparatus. I can easily see how in like degree the physician and apothecary, would be benefited by the use of normal remedies, and the consequent unification of doses. 