None
The electrolytic behaviour of thallium, iridium, vanadium, palla- dium, molybdenum, selenium, and tellurium has been examined by L. Schucht. He finds that thallium is not deposited under the influence of the current from a solution of the sulphate or nitrate containing free acid. The precipitation from a neutral solution is also incomplete, owing to the liberation of gas. From an ammoniacal solution lead-grey metallic thallium is deposited at the negative elec- trode, with a strong escape of gas, and blackish -brown thallium oxide at the positive electrode. The result is the same in a solution of thallium supersaturated with potash. From alkaline solutions the precipitation is complete. Iridium is deposited as a bluish-white metal at the negative elec- trode if the sulphate is submitted to electrolysis. With solutions containing organic acids iridium is also deposited in a firmly- adherent state, with abundant escape of gas. On the electrolysis of vanadium chloride dissolved in water con- taining hydrochloric acid there is no precipitation. The blue colour of the solution changes to green and violet, the vanadic acid being reduced to vanadous oxide. An aqueous solution of palladious nitrate, acidified with a few drops of nitric acid, gives, immediately on closing the circuit, a 684 SELECT METHODS IN CHEMICAL ANALYSIS. bronze-coloured deposit at the negative pole, which ultimately appears black. At the positive pole there appears a slight deposit of oxide of a red colour. In alkaline solutions of palladious oxide the precipitation is much slower, and oxide also appears. From the ammoniacal solution of molybdic acid molybdous oxide, is deposited. Coloured rings appear at the negative pole ; they become denser and take a deep blue-black colour. The precipitation is accom- panied with a free escape of gas, and is complete. The deposit adheres very firmly. In acid solutions there is no precipitation. Selenium is deposited both from acid and alkaline solutions at the negative pole, at first as a light brownish-red coating, which gradually becomes thicker and darker. The precipitation is perfect. As the deposit does not adhere firmly to the platinum cone, Schucht oxidizes the selenium by boiling with nitric acid, and adds the solution of some salt the metal of which is thrown down by the current in a solid form,, and thus obtains a firmly-adhesive deposit of selenium. He prefers for this purpose a solution of copper. The positive pole is covered with a dark coating which dissolves in hydrochloric acid with a yellow colour. The author ascribes this precipitation to the action of hydrogen selenide. Tellurium behaves similarly to selenium, but is much more easily reduced by electrolysis. Analysis of the Gold and Platinum Salts of Organic Bases. M. C. Scheibler dissolves a weighed quantity of the acid or platinum salt in water, or if it does not happen to be readily soluble, keeps it suspended therein, and places it in contact with metallic magnesium, whereby the metals gold and platinum are separated, and hydrogen is at the same time evolved. This operation is carried on at the ordinary temperature, or if the salts are difficultly soluble, on a water-bath ; the fluid may be acidified, but not with hydrochloric acid, since the object often may be to estimate chlorine also. The ribbon-like magnesium wire met with in commerce is- sufficiently pure for this purpose. The gold and platinum separated during this operation are, by means of careful decantation, freed from the fluid wherein they are immersed, and next transferred to a filter and washed, first with distilled water, and next, after the filtrates intended for the estimation of chlorine have been set aside, with dilute hydrochloric acid, in order thereby to remove any excess of magnesium or any magnesia which might remain mixed with or ad- herent to these metals ; after having been well purified and dried the metals are ignited and weighed. The results obtained by this method are very correct. COREECT ADJUSTMENT OF WEIGHTS. 685 To Prevent the Bumping of Boiling Liquids. In cases where the introduction of any foreign matter into the liquid about to be distilled is undesirable, Dr. Hugo Miiller, F.E.S., introduces through the cork in the tubulure of the retort a glass tube, which is drawn out to a long capillary tube and pressed tightly to the "bottom of the retort. The upper end of the glass tube is connected, T>y means of an india-rubber tube, with a generator of carbonic acid, or hydrogen, or a gas-holder containing air, and whilst the distillation is going on, one of these gases is passed in a slow but continuous current through the liquid. Under these conditions, all bumping is avoided, and the distillation proceeds with the utmost facility. For ordinary, purposes, however, it is still more convenient to introduce into the liquid about to be distilled a small fragment of sodium amalgam or, in cases where the liquid is acid, a small piece of sodium-tin. Methylic alcohol is well known to be one of the most difficult liquids to distil ; yet, on the introduction of a minute piece of sodium amalgam or sodium-tin, it can be distilled without the slightest inconvenience. On one occasion Dr. Miiller found that more than 400 grammes of methylic alcohol distilled over with perfect steadiness, and without exhausting the activity of a fragment of sodium- tin, weighing not more than 0'06 gramme. It is, perhaps, hardly necessary to mention that the action of sodium amalgam and sodium-tin is due to a minute but continuous disengagement of hydrogen taking place during the process of dis- tillation. On the Correct Adjustment of Chemical Weights. The following description of the method adopted for adjusting a set of platinum weights is taken from the author's Memoir on the Atomic Weight of Thallium.1 A set of weights as ordinarily supplied by even the best instrument- makers is never absolutely exact ; however carefully they may be ad- justed, the pieces of metal which respectively represent 1000 grains, 100 grains, 10 grains, &c. are only more or less approximations to the true weights. In most chemical analyses, the error arising from such inaccuracies in the weights used is so small, in comparison to errors of manipulation or to imperfections inherent in the chemical processes adopted, that it may generally be disregarded ; but when the chemist has for his object the estimation of an atomic weight, or is engaged in other researches demanding the highest refinement of accuracy which chemistry and physics can supply, then he is bound to neglect no correction which will increase the precision of the results. That chemists whose well- trained reasoning powers allow 1 Phil. Trans. 1873, p. 277. 686 SELECT METHODS IN CHEMICAL ANALYSIS. them to take for granted nothing which is not capable of experimental verification, and who insist upon the utmost attainable precision in their balances, should, as a rule, neglect the probable errors which the inaccuracies of their weights may introduce, is somewhat incon- sistent. The weights employed in the experiments were of platinum. The platinum was quite pure ; it was fused, cast, and then well hammered. The weights were adjusted by myself during May, June, July, and August, 1864 : they were first roughly adjusted, and then the specific gravity of each weight was taken. The weights were heated to red- ness in a bath of magnesia previous to ascertaining their specific gravity. The density of the larger weights was ascertained to the second place of decimals, and that of the smaller ones to the first place. The record of the final adjustment of these weights will be sufficient to show the method adopted. In taking the specific gravity of the weights, the distilled water was contained in a glass beaker of about 250 cubic inches capacity. Each weight was suspended by a fine platinum wire to be attached to the pan of the balance. With this wire affixed the weight was introduced into a small glass vessel filled with water, and heated over a spirit- lamp to the boiling-point. When all the air-bubbles had been expelled by this process, the small jar containing the weight was lowered into the water in the beaker, the weight, on removing the small jar, being perfectly free from any adhering bubbles of air. After the tempera- ture had sunk to the proper point, the specific gravity was taken. The 1000-grain weight was selected as the standard : for in nearly every process in which weights are used in chemistry, the object is not to ascertain the absolute weight of a substance in terms of a grain or gramme, but to estimate its relative weight in comparison with that which it possessed at some other time before it was submitted to cer- tain analytical or synthetical operations. If the weighings are per- formed with the same weights, it does not at all matter whether the weights are absolutely of the value which they profess to be ; but it is very important that they should bear a known proportion to each other. This must be understood as referring only to ordinary chemical re~ search in synthesis or analysis. In many physical investigations it is of great importance that the 1000-grain weight should really represent 1000 normal grains, or that its deviation from that value should be accurately estimated ; but I confess I do not know where a standard weight suitable for such a comparison is to be met with. The weights at first tried were far from accurate among themselves. I accordingly ascertained their errors by the method described below, and then ad- justed them myself according to the corrections thus found necessary. The residual errors in the weights were then finally taken in the following manner : The balance being brought into equilibrium and the temperature CORRECT ADJUSTMENT OF WEIGHTS. 687 and barometrical pressure carefully noted, the 1000-grain weight was placed in the left pan, and in the right the 600, the 300, and the 100- grain weights. It was now found that, to bring the balance back to equilibrium, a slight additional weight had to be placed on the right side to supplement the three weights already in that pan. This was noted. The weights were then removed to the opposite sides, the 1000-grains being on the right and the three smaller weights on the left. It was now found that a small weight had to be subtracted from the side carrying the three weights in order to produce equilibrium. The weights were removed and interchanged in this manner ten times, so as to eliminate, as far as possible, the errors arising from observa- tion, or the unequal expansion by heat of the arms of the balance ; and by applying the method of least squares to the results obtained, the following equation was arrived at : (1000) = (600) + (300) + (100) + 0- 01 ... a, the figures within parentheses representing the nominal value of the actual pieces of platinum stamped 1000, 600, 100 grains, &c. In a similar manner the values of the remaining weights were ascertained ; thus : (600) = (300) + (200) + (100) + 0-00777 ... 6. (300) = (200) + (100) + 0-00991 . . . c. (200) = (100) + (60) + (30) + (10) + 0-01577 . d. (100)= (60)+ (30)+ (10) - 0-00030 . e. (60)= (30)+ (20)+ (10) - 0-00522 . . . /. (30)= (20)+ (10) + 0-00154 . g. (20)= (10)+ (6)+ (3)+ (1) + 0-00355 . . . ft. (10)= (6)+ (3)+ (1) + 0-00052 . . . i. (6)= (3)-t- (2)+ (1) - 0-00102 . . . j. (3)= (2)+ (1) + 0-00165 . . . k. (2)= (1) + (-6)+ (-3)+ (-1) - 0-00312 . Z. (1)= (-6)+ (-3)+ (-1) - 0-00508 . . . m. (•6)= (-3)+ (-2)+ (-1) - 0-00260 . n. (•3)= (-2)+ (-1) + 0-00225 ... o. (-2) = (-1) + (-06) + (-03) + (-01) - 0-00100 . p. (•1) = (-06) + (-03) + (-01) - 0-00802 . q. (•06) = (-03) + (-02) + (-01) - 0-00607 . . . r. (-03)= (-02)+ (-01) - 0-00642 . s. (•02) = (-01) + (-Clr")1 - O-OOllSr' . t. (-01) = (-Olr") + 0-00413/ . u. (•01)- (-01/) + 0-004W. . . v. We have now the data for ascertaining the absolute values of the weights in terms of the (1000) weight taken as standard. Adding the equations a and b gives (1000) = 2(300) + (200) + 2(100) + 0-01777. Multiplying equation c by 2 gives 2(300) =2(200) + 2(100) + 0-01982. 1 r', r" represent riders, two of which were adjusted in this manner. 688 SELECT METHODS IN CHEMICAL ANALYSIS. Subtracting e from d gives (200) = 2 (100) +0-01607. Now by (a + b) + 2c + 3(d — e) we get (1000) = 10(100) + 0-01777 + 0-01982 + 0-04827 ; /.(1000) = 10(100) + 0-0858 ; />(iooo)= (100) + 0-00858; /. (100)= 100 -0-00858; /.(100) = 99-99142 grains . . .A.1 Substituting this value for the (100) weight, we get from equations, 99-99142 = (60) + (30) + (10) -0-0003 : .-.(60) + (30) + (10) = 99-99172 . B. From equation d we therefore get (200) = 99-99142 + 99-99172 + 0-01577 ; .-.(200) = 199-99891 . . , . . C- From equation c we get (300) = 199-99891 + 99-99142 + 0-00991 ; /.(300) =300-00024 D- From equation b we get (600) = 300-00024 + 199-99891 + 99-99142 + 0-00777 ; .'.(600) =599-99834 ..... E. Again, adding e and /, (100) = 2(30) + (20) + 2(10) - 0-00552 ; /.from A, 99-99142 = 2(30) + (20) + 2(10) -0-00552. Multiplying g by 2, 2(30) = 2(20) + 2(10) + 0-00308. Subtracting i from h, (20) = 2(10) + 0-00303. By adding e, f, twice g, and thrice the last equation, we get 99-99142 = 10(10) + 0-000665 ; /. (10) = 9-998477 F. From equation i we get 9-998477 = (6) + (3) + (1) + 0-00052 ; .-. (6) + (3) + (!) = 9-997957. . G. Substituting these values in h, we get (20) = 9-998477 + 9-997957 + 0-00355 ; /. (20) = 19-999984 . . • . . . H. From g we get (30) = 19-999984 + 9-998477 + 0-00154 ; .'.(30) = 29-999991 I. 1 Although these decimals are carried to the sixth place, the balance would not indicate beyond the fourth place. By taking the mean of ten interchanged weigh- ings, I could obtain a fifth place. The calculated values of the weights were carried to a sixth decimal, in order to avoid inaccuracy in the fourth and fifth places when several values were summed. COEEECT ADJUSTMENT OF WEIGHTS. 689s From / we get (60) = 29-999991 + 19-999984 + 9-998477 - 0-00522 ; .-.(60) = 59-993232 . ... . J_ Again, adding i and j, (10) = 2(3) + (2) + 2(1) -0-0005. Multiplying & by 2, 2 (3) = 2 (2) + 2(1) + 0-0033. Subtracting m from Z, (2) = 2(1) + 0-00196. Then (i +j) + 2& +- 3(1 - m) gives (10) + 10(1) + 0-00868 ; .'.9-998477 = (10)1 + 0-00868 ; /.0-9998477 = (1) + 0-000868 ; /.(I) = 0-9989797 K. From equation m we have 0-9989797= (-6) + (-3) + (-1) -0-00508 ; .-.(•6) + (-3) + (•!) = 1-0040597 . . v. From I, (2) = 0-9989797 + 1-0040597 - 0-00312 ; /.(2) = 1-9998394 M. From k, (3) = 1-9998394 + 0-9989797 + 0-00165 ; .-.(3) = 3-0004691 N. From y, (6) - 3-0004691 + 1-9998394 + 0-9989797 - 0-00102 ; .-.(6) = 5-9982682 O. Again, adding m and n, (1) = 2(-3) + (-2) + 2(-l) - 0-00768. Multiplying o by 2 we get 2(-3) = 2(-2) + 2(-l) + 0-0045. Subtracting q from p, (-2) = 2(-l) + 0-00702. Then (m +ri) + 2o + S(p — q) gives (1) = 10 (-1) + 0-01788; .-.0-9989797 = 10(-1) + 0-01788 ; /.0-09989797 = (-1) + 0-001788 ; .-.(•I) =0-09810997 P.. From q we get 0-09810997 = (-06) + (-03) + (-01) -0-00802 ; .'. (-06) + (-03) + (-01) = 0-10612997 . . Q.. From p, (-2) + 0-09810997 + 0-10612997 - 0-001 ; .-.(•2) =0-20323994 E. Y Y €90 SELECT METHODS IN CHEMICAL ANALYSIS. From o, (•3) = 0-20323994 + 0-09810997 + 0-00225 ; .-. (-3) =0-30359991 S. From n we get (•6) = 0-30359991 + 0-20323994 + 0-09810997 - 0-0026 ; /. (-6) =0-60234982 T. Again, adding q and r, (-1) = 2(-03) + (-02) + 2(-01) -0-01409. Multiplying s by 2 we get 2(-03) = 2(-02) + 2(-01) -0-01284. Subtracting u from t, (-2) = 2(-01)- 0-00531. s + 8(*-tt) gives - 0-04286, /.0-09810997 = 10(-01) - 0-04286, .-.0-009810997 = (-01) -0-004286, .-.(•01) = 0-014096997 . U. From u we get 0-014096997 = (-Olr") + 0-00413, /.(•Olr") = 0-009966997 . V. From t we get (-02) = 0-014096997 + 0-009966997 - 0-00118, .-.(•02) = 0-022883994 . . . . W- From s we get (-03) = 0-022883994 -h 0-014096997-0:00642, .-.(•03) =0-030560991 . . . . X. From r we get (-06) = 0-030560991 + 0-22883994 + 0-014096997 - 0-00607, .-.(•06) = 0-061471982. . . . . Y. From v we get 0-014096997 = ('Olr') -f 0-0041, /. (.Olr') =0-009996997 . Z. The value of the weights thus given was, however, their weight in of the ordinary pressure ; it became therefore necessary to ascertain their value in a vacuum. All bodies displace a bulk of air equal to their own volume, and the weight of this air is of course greater as their specific gravity diminishes. In delicate investigations this loss of weight is important. The reduction of the platinum weights to their true value in vacuo was calculated by the following formula : — Let W = weight in air, 10= „ ,, water, a = specific gravity of air as compared with water ; then . , . . W— aw x, or weight in vacuo, = — , where a = 0-001225, and lia-b-998775. CORRECT ADJUSTMENT OF WEIGHTS. 691 The following Table shows the final results of these adjustments : — Nominal Value True Value in Air at Weight of Air Volume in Water of of Weights 30 in.1 62° F. Displaced Maximum Density grs. gTS. J?r. grs. 1000-00 1000-000000 0-058271 47-5100 600-00 599-998340 0-035533 28-9700 300-00 300-000240 0-017501 14-2700 200-00 199-998910 0-011664 9-5100 100-00 99-991420 0-005887 4-8000 60-00 59-993232 0-003483 2-8400 30-00 29-999991 0-001668 1-3600 20-00 19-999984 0-001104 0-9000 10-00 9-998477 0-000490 0-4000 6-00 5-998268 0-000355 0-2900 3-00 3-000469 0-000171 0-1400 2-00 1-999839 0-000113 0-1000 1-00 0-998980 0-000055 0-0400 0-60 0-602350 0-000035 0-0300 0-30 0-803600 0-000017 0-0200 0-20 0-203240 0-000011 o-oioo 0-10 0-098110 0-000005 0-0040 0-06 0-061472 0-000003 0-0030 0-03 0-030561 0-000002 0-0020 0-02 0-022884 0-000001 0-0010 o-oi 0-014097 0-000001 0-0004 0-01' 0-009997 0-000001 0-0004 0-01" 0-009967 o-oooooi 0-0004 The value of each weight in air, plus the weight of air displaced, is the weight in vacuo. Having ascertained their true value, the weights were carefully preserved; and as, being of platinum, there was no accumulation of tarnish on their surface, and as they were lifted with ivory- tipped forceps to prevent wear, they have shown up to the present time, whenever compared, absolutely no alteration. 1 The cistern of the barometer is 115 feet above the approximate mean water- level at Somerset House. Y 2 €92 SELECT METHODS IN CHEMICAL ANALYSIS. CHAPTEK XVI. USEFUL TABLES. Conversion of Centigrade and Fahrenheit Degrees. 1° C. = 1-8° F. = £ ° F. 1° C. x f = IF. 1° F. x § = 1° C. To convert Fahrenheit into Centigrade — Subtract 32 from the original number, and divide the remainder by 1'8, thus: 176° F.— 32 -4- 1-8 = 80° Cent. To convert Centigrade into Fahrenheit, multiply by 1*8, add 32 to the product, thus : 80° Cent, x 1-8 + 32 = 176° F. With the aid of a scale like the accompanying one,1 thermometric degrees may be converted from one to the other with the greatest accuracy without making any calculations. A simple inspection of the diagram will suffice to show the principle upon which the scale is constructed. Each degree Fahrenheit is divided into 5 parts, and each degree Centigrade into 9 parts, which are intended to represent fractions of a degree ; the degrees themselves being numbered consecutively from the freezing-point of each ther- mometer upwards. A few examples will best explain the use of this scale. Suppose the temperature of a body to be 40° F. and it is required to know what degree that is on the Centigrade scale. By looking for the next degree Centigrade above 40° F. on the scale, it is found to be 4, and 4 of the small divisions after it ; 40° F. are therefore equivalent to 4'4° C., or, repeating the decimal figure for greater accuracy, 4*44° C. When Centigrade degrees have to be reduced to degrees of Fahren- heit, the decimal figures of the latter must be doubled to obtain the correct answer. For example, it is required to represent 3° C. by their Fahrenheit equivalent ; referring to the scale we find the next degree Fahrenheit above 3° C. to be 37*2°, and doubling the decimal figure we have the correct answer 37*4° F. Again, taking the outer columns of figures at the same place, we find 43° C. corresponding to 109'4° F. 1 By Mr. Birney. CONVERSION OF FEENCH & ENGLISH WEIGHTS & MEASURES. 693 FAHRENHEIT. CENTIGRADE OR CELSIUS. 140 104 68 32 = 0 20 40 60 141 105 69 33 =- 142 106 70 34 ~ '' l 21 41 61 % % » ae^2 " «• - Z no9 n 23 « 63 147 111 75 39 — SEE- 4 24 44 64 148 112 76 40 _ =- 149 113 77 41 ^ 5 25 45 65 150 114 78 42 =•_ 151 115 79 43 _J^- — 6 26 46 66 152 116 80 44 _JpL 153 117 81 45 _z.^r- 7 27 47 67 154 118 82 46 _H±_ 8 28 48 68 155 119 83 47 — 156 120 84 48 ._===-- . 9 2g 49 69 157 121 85 49 =. 158 122 86 50 — JH 10 30 50 70 159 123 87 51 _=- 160 124 88 52 _rf=£=- 11 31 51 71 161 125 89 53 ._.=^ 162 126 90 54._Jpz-12 82 52 72 163 127 91 55 _s_ „ 53 ?3 164 128 92 56 _ 165 129 93 57 -=^_U 34 54 74 166 130 94 58 _=_ 367 131 95 59 f=| 15 35 55 75 168 132 96 60 _~ iH- 169 133 97 61 -^g§=— 16 36 56 76 170 134 98 62 ~^— 171 135 99 63 _rft— " 37 57 77 172 136 100 64 — =- 1ft «« ,,« 7ft 173 137 101 ' 65 - ^~18 "8 °8 ?8 17* 138 102 66 -^=^=^319 39 59 79 175 139 103 67 =^- Tables for the Mutual Conversion of French and English Weights and Measures. The equivalents in one system of the weights and measures of the other system can readily be found by means of the following tables. By changing the position of the decimal point, the tables are available for all decimal multiples and subdivisions of these quantities ; for instance, in order to find the part of a gramme which corresponds to 0*1, 0*01, O'OOl, &c., of a grain, it is necessary to advance the decimal point one, two, or three places to the left. In the same manner it is advanced to the right for the purpose of finding the grammes corre- sponding to 10, 100, 1000, &c., grains. 694 SELECT METHODS IN CHEMICAL ANALYSIS. For example : — In the table for the conversion of grammes into grains, it is required to find the equivalent in grains of 6*4481 grammes. From number 6 (without altering the place of the decimal point) 92-6304 1 From number 4 (advancing the decimal point one place to the left). . 6-1753 1 From number 4 (advancing the decimal point two places to the left) 0-6175 1 From number 3 (advancing the decimal point three places to the left) . 0-0463 1 From number 1 (advancing the decimal point four places to the left) 0-0015 Therefore 6-4431 grammes are equal to .... 99-^710 grains. Grammes into Grains. Grammes Grains Grammes Grains Grammes Grains 1 = 15-4384 4 = 61-7536 7 = 108-0688 2 = 30-8768 5 = 77-1920 8 = 123-5072 3 = 46-3152 6 = 92-6304 9 = 138-9456 Grains into Grammes. Grains Grammes Grains Grammes Grains Grammes 1 = 0-06477 4 = 0-25908 7 = 0-45339 2 = 0-12954 5 = 0-32385 8 = 0-51816 3 = 0-19431 6 = 0-38862 9 = 0-58293 Pounds into Kilogrammes. Pounds Kilogrammes Pounds Kilogrammes Pounds Kilogrammes 1 = 0-4534148 4 - 1-8136592 7 = 3-1739036 2 = 0-9068296 5 = 2-2670740 8 = 3-6273184 3 = 1-3602444 6 = 2-7204888 9 = 4-0807332 Kilogrammes into Pounds. Kilogrammes Pounds Kilogrammes Pounds Kilogrammes Pounds 1 = 2-205486 4 = 8-821944 7 - 15-438402 2 = 4-410972 5 = 11-027430 8 = 17-643888 3 = 6-616458 6 = 13-232916 9 = 19-849374 Inches into Centimetres t Inches Centimetres Inches Centimetres Inches Centimetres 1 _ 2-539954 4 = 10-1598 7 = 17-7797 2 = 5-079900 5 = 12-6998 8 = 20-3196 3 = 7-619900 6 = 15-2397 9 =* 22-8596 1 In almost every case when the decimal point is moved to the left, the last figures may be omitted without introducing any appreciable error. CONVERSION OF FRENCH AND ENGLISH MEASURES. 695 Centimetres into Inches. Centimetres Inches Centimetres Inches Centimetres Inches 1 = 0-3937079 4 = 1-5748316 7 = 2-7559553 2 = 0-7874158 5 = 1-9685395 8 = 3-1496632 3 = 1-1811237 6 - 2-3622474 9 = 3-5433711 Feet into Metres. Feet Metres Feet Metres Feet Metres 1 = 0-3047945 4 = 1-2197680 7 = 2-1335614 2 = 0-6095890 5 = 1-5239724 8 = 2-4383559 3 = 0-9143835 6 = 1-8287669 9 = 2-7431504 Metres into Feet. Metres Feet Metres Feet Metres Feet 1 = 3-2808992 4 = 13-1235968 7 = 22-9662944 2 = 6-5617984 5 = 16-4044960 8 = 26-2471936 3 = 9-8426976 6 = 19-6853952 9 = 29-5280928 Miles into Kilometres. Miles Kilometres Miles Kilometres Miles Kilometres 1 = 1-6093 4 = 6-4373 7 - 11-2652 2 = 3-2186 5 = 8-0466 8 = 12-8745 3 = 4-8279 6 - 9-6559 9 = 14-4838 Kilometres into Miles. Kilometres Miles Kilometres Miles Kilometres Miles 1 = 0-62138 4 = 2-48552 7 = 4-34966 2 = 1-24276 5 = 3-10690 8 .= 4-97104 3 = 1-86414 6 = 3-72828 9 = 5-59242 Square Feet into Square Metres. Sq. Feet Sq. Metres Sq. Feet Sq. Metres Sq. Feet Sq. Metres 1 = 0-0929 4 = 0-3716 7 = 0-6503 2 = 0-1858 5 = 0-4645 8 = 0-7432 3 = 0-2787 6 = 0-5574 9 = 0-8361 Square Metres into Square Feet. Sq. Metres Sq. Feet Sq. Metres Sq. Feet Sq. Metres Sq. Feet 1 = 10-7698 4 = 43-0792 7 = 75-3886 2 = 21-5396 5 = 53-8490 8 = 86-1584 3 = 32-3094 6 = 64-6188 9 = 96-9282 Cubic Feet into Cubic Metres. Cub. Feet Cub. Metres Cub. Feet Cub. Metres Cub. Feet Cub. Metres 1 = 0-028314 4 = 0-113256 7 = 0-198198 2 = 0-056628 5 = 0-141570 8 = 0-226512 3 = 0-084942 6 == 0-169884 9 = 0-254826 696 SELECT METHODS IN CHEMICAL ANALYSIS. Cub. Metres Cub. Feet 1 = 35-3171 2 = 70-6342 3 = 105-9513 Cubic Metres into Cubic Feet. Cub. Metres Cub. Feet 4 = 141-2684 5 = 176-5855 6 = 211-9026 Cub. Metres 7 = 8 = Cub. Feet 247-2197 282-5368 317-8539 Long Tons 1 = Long Tons into Tonnes of 1000 Kilos. Tonnes of 1000 Kilos. 1-015649 2-031298 3-046947 Long Tons 4 = 5 - 6 = Tonnes of 1000 Kilos. 4-062596 5-078245 6-093894 Long Tons n __ Tonnes of 1000 Kilos. 7-109543 8-125192 9-140841 Pounds per Square Inch into Kilogrammes per Square Centimetre. Pounds per Kilos, per Sq. Inch Sq. Centim. 1 = 0-0702774 Pounds per Kilos, per Sq. Inch Sq. Centim. 4 tm 0-2811096 Pounds per Sq. Inch 7 _ Kilos, per Sq. Centim. 0-4919418 2 = 0-1405548 5 = 0-3513870 8 = 0-5622192 3 = 0-2108322 6 = 0-4216644 9 = 0-6324966 Kilogrammes per Square Millimetre into Pounds per Square Inch. Kilos, per Pounds per Sq. Millim. Sq. Inch 1 = 1425-45 Kilos, per Pounds per Sq. Millim. Sq. Inch 4 --= 5701-80 Kilos, per Pounds per Sq. Millim. Sq. Inch 7 -% 6978-15 2 = 2850-90 5 = 7127-25 8 = 11403-60 3 = 4276-35 6 = 8552-70 9 = 12829-05 Belative Values of Trench and English Weights and Measures. WEIG HTS. Milligramme . = 0-015438395 troy grain Centigramme . = 0-15438395 >» M Decigramme . = 1-5438395 M » 15-438395 »> 0-643 pennyweight 0-03216 oz. troy » • • . ' . . = 0-03527 oz. avoirdupois Decagramme . = 154-38395 troy grains »> • . = 5-64 drams avoirdupois Hectogramme. . = 3-2154 ozs. troy »> • . = 3-527 ozs. avoirdupois Kilogramme . = 2-6803 Ibs. troy » • . = 2-205486 Ibs. avoirdupois Myriagramme. • • ™ 26-803 Ibs. troy » . = 22-05486 Ibs. avoirdupois Quintal metrique . = 100 kilos. = 220-5486 Ibs. avoir. 'Tonne . = 1000 „ 2205-486 DIFFERENT VALUES OF THE GRAMME. 697 Different authors give the following values for the gramme : — Gramme — 15*44402 troy grains = 15-44242 = 15-4402 = 15-433159 = 15-43235 Avoirdupois. Long ton = 20 cwt. -- 2240 Ibs. = 1015-649 Short ton (2000 Ibs.) . . - 906-8296 Hundredweight (112 Ibs.) . = 50-78245 Quarter (28 Ibs.). Pound = 16 ozs. Ounce = 16 drams = 437-5 grs. = Dram = 27-344 grains = Grain . . = 0-064773 kilogrammes 12-6956144 7000 grs. = 453-4148 grammes 28-3375 1-77108 gramme Troy (Precious Pound = 12 ozs. = 5760 grs. Ounce = 20 dwts. = 480 „ Pennyweight . . = 24 ,, Grain . . . = 373-096 grammes 31-0913 1-55457 gramme 0-064773 Troy (Pharmacy}. Ounce — 8 drams = 480 grs. = 31-0913 grammes Dram = 3 scruples = 60 „ - 3-8869 Scruple = . . . . = 20 „ = 1-29546 gramme Inch (£th yard) Foot (£rd yard). Yard. Mile (1760 yards) MEASURES OP LENGTH. Millimetre = 0-03937 inch Centimetre = 0-393708 Decimetre - 3-937079 inches Metre = 39-37079 = 3-2808992 feet 1-093633 yard rd) . = 2-539954 d) . = 3-0479449 centimetres decimetres 0-91438348 metre 1609-3149 metres SUPERFICIAL MEASURES. Square millimetre ,, centimetre ,, decimetre »i >» • „ metre or centiare il^th of a square 0-00155 0-155086 „ 15-5086 0-10769 „ 1550-86 10-7698 1-196033 , inches foot inches feet yard 698 SELECT METHODS IN CHEMICAL ANALYSIS. Are Hectare »> • Square inch. foot. ,, yard .... Acre (4840 square yards) 1076-98 „ feet 119-6033 ,, yards 0-098845 ,, rood 11960-33 „ yards 2-471143 ,, acres 645-109201 ;, millimetres 6-45109 „ centimetres 9-2903 ,, decimetres 0-836097 ,, metre 0-404671 „ hectare MEASURES OF CAPACITY. Cubic millimetre ,, centimetre 10 cubic centimetres 100 1000 U >> »l Decalitre . = 0-000061029 cubi< . = 0-061029 '. . = 0-61029 . - 6-10295 or litre . . = 61-0295688 1-760773 imper = 0-2200967 . = 610-295688 cubic . - 2-2009668 imp. j 3 inch n «i inches ial pint gallon inches gallons feet gallons yard feet Hectolitre. Cubic metre. . = 3-5317 cubic . • = 22-009668 imp. j . = 1-308 cubic . - 35-3171 „ Cubic inch „ foot ,» yard = 16-3855 cubic centimetres = 28-3159 „ decimetres = 0-764520696 „ metre BRITISH IMPERIAL MEASURES. Pint (£ gallon) Quart (i „ ) Imperial gallon = 0-567932 litre = 1-135864 = 4-54345797 litres WEIGHT OF WATER, &c. 1 cubic inch 1 pint ( = 34-65 cubic inches). 1 cubic foot ( = 6-25 galls., or 1000 ozs.). 1 gallon ( = 277-274 cubic inches). 1-8 cubic foot 35'84 cubic feet . ^ ' .. 11-20 gallons . . *. 224-0 „ A cubic inch of mercury - 3425-25 grains. 252-45 grs. 1-25 Ib. 62-50 Ibs. 10-00 Ibs. 1 cwt. 1 ton. 1 cwt. 1 ton. Baume's Hydrometer. The following tables give the comparison of the degrees of Baume's hydrometer with the specific gravity : — BAUME'S HYDKOMETEE. 699 Table for Liquids Heavier than Water. Degrees Baume Specific Gravity Degrees Baume Specific Gravity Degrees Baume Specific Gravity 0 1-000 26 1-206 52 1-520 1 1-007 27 1-216 53 1-535 2 1-013 28 1-226 54 1-551 3 1-020 29 1-236 55 1-567 4 1-027 30 1-246 56 1-583 5 1-034 31 1-256 57 1-600 6 1-041 32 1-267 58 1-617 7 1-048 33 1-277 59 1-634 8 1-056 34 1-288 60 1-652 9 1-063 35 1-299 61 1-670 10 1-070 36 1-310 62 1-689 11 1-078 37 1-322 63 1-708 12 1-086 38 1-333 64 1-727 13 1-094 39- 1-345 65 1-747 14 1-101 40 1-357 66 1-767 15 1-109 41 1-369 67 1-788 16 1-118 42 1-382 68 1-809 17 1-126 43 1-395 69 1-831 18 1-134 44 1-407 70 1-854 19 1-143 45 1-421 71 1-877 20 1-152 46 1-434 72 1-900 21 1-160 47 1-448 73 1-924 22 1-169 48 1-462 74 1-949 23 1-178 49 1-476 75 1-974 24 1-188 50 1-490 76 2-000 25 1-197 51 1-505 Table for Liquids Lighter than Water. Degrees Baume Specific Gravity Degrees Baume Specific Gravity Degrees Baume Specific Gravity 10 1-000 27 0-896 44 0-811 11 0-993 , 28 0-890 45 0-807 12 0-986 29 0-885 46 0-802 13 0-980 30 0-880 47 0-798 14 0-973 31 0-874 48 0-794 15 0-967 32 0-869 49 0-789 16 0-960 33 0-864 50 0-785 17 0-954 34 0-859 51 " 0-781 18 0-948 35 0-854 52 0-777 19 0-942 36 0-849 53 0-773 20 0-936 37 0-844 54 0-768 21 0-930 38 0-839 55 0-764 22 0-924 39 0-834 56 0-760 23 0-918 40 0-830 57 0-757 24 0-913 41 0-825 58 0-753 25 0-907 42 0-820 59 0-749 26 0-901 43 0-816 60 0-745 700 SELECT METHODS IN CHEMICAL ANALYSIS. Twaddell's Hydrometer. To convert degrees of Twaddell's hydrometer into specific gravity, multiply the number by 5, and add 1000 to the product. Example. 25 Twaddell x 5 + 1000 = 1125 specific gravity. To reduce specific gravity into degrees Twaddell, deduct 1000 from the number, and divide the remainder by 5. Example. Specific gravity 1125-1000-4-5 = 25 Twaddell. Percentage of Soda in Aqueous Solutions of Various Specific Gravities* Temp. 15°. Specific Gravity Na20.p.c. Specific Gravity NaaO. p.c. Specific Gravity NaaO. p.c. 1-015 1 1-190 13 1-355 25 1-020 2 1-203 14 1-369 26 1-043 3 1-219 15 1-381 27 1-058 4 1-233 16 1-395 28 1-074 5 1-245 17 1-410 29 1-089 6 2-258 18 1-422 30 1-104 7 •270 19 1-488 35 1-119 8 •285 20 1-558 40 1-132 9 •300 21 1-623 45 1-145 10 •315 22 1-690 50 1-160 11 •329 23 1-760 55 1-175 12 1-341 24 1-830 60 Percentage of Caustic Potash in Aqueous Solutions of Various Specific Gravities. Temp. 15°. Specific Gravity K.,0. p.c. Specific Gravity KaO. p.c. Specific Gravity K20. p.c. 1-0050 0-5658 1-1182 11-882 1-30 29-34 1-0153 1-6970 1-1437 14-145 1-34 32-14 1-0260 2-8290 1-1702 16-408 1-38 34-74 1-0369 3-9610 1-1979 18-671 1-42 37-97 1-0478 5-0020 1-2268 20-935 1-46 42-31 1-0589 6-2240 1-2493 22-632 1-50 46-45 1-0703 7-3550 1-2805 24-895 1-54 50-09 1-0819 8-4870 1-3131 27-158 1-58 53-06 1-0938 9-6190 SPECIFIC GRAVITY TABLES. 701 Percentage of Ammonia in Aqueous Solutions of Various Specific Gravities. Temp. 14°. Specific Gravity NH3 p.c. Specific Gravity NH3 p.c. Specific Gravity NH3 p.c. •8844 36 •9133 24 •9520 12 •8864 35 •9162 23 •9556 11 •8885 34 •9191 22 •9593 10 •8907 33 •9221 21 •9631 9 •8929 32 •9251 20 •9670 8 •8953 31 •9283 19 •9709 7 •8976 30 •9314 18 •9749 6 •9001 29 •9347 17 •9790 5 •9026 28 •9380 16 •9831 4 •9052 27 •9414 15 •9873 | 3 •9078 26 •9449 14 •9915 2 •9106 25 •9484 13 •9959 1 Percentage of Nitric Acid in Aqueous Solutions of Various Specific Gravities. Temp. 15°. Specific Gravity HN03 p.c. Specific Gravity HN03 p.c. 1 1 Specific Gravity HN03p.c. 1-010 2-00 1-225 36-00 1-429 71-24 1-022 4-00 1-251 40-00 1-438 74-01 1-045 7-22 1-274 43-53 1-451 77-66 1-067 11-41 j 1-298 47-18 1-463 80-96 1-077 13-00 1-323 50-99 1-474 84-00 1-089 15-00 i 1-339 53-81 1-482 86-17 1-105 17-47 1-353 56-10 1-494 89-56 1-120 20-00 1-372 59-59 1-506 93-01 1-138 23-00 1-381 61-21 1-514 95-27 1-166 27-00 1-400 65-07 1-523 97-89 1-185 30-00 1-410 67-00 1-530 99-72 1-211 33-86 1-419 69-20 1-530 100-00 702 SELECT METHODS IN CHEMICAL ANALYSIS. Percentage of Sulphuric Acid in Aqueous Solutions of Various Specific Gravities. Temp. 15°. Specific Gravity HaS04p.c. Specific Gravity HaSO« p.c. Specific Gravity H2S04 p.c. 1-0064 1 1-1060 15 1-2890 38 1-0130 2 1-1136 16 1-3060 40 1-0190 3 1-1210 17 •3510 45 1-0256 4 1-1290 18 •3980 50 1-0320 5 1-1360 19 •4480 55 1-0390 6 1-1440 20 •5010 60 1-0464 7 1-1590 22 •5570 65 •0536 8 1-1740 24 •6150 70 •0610 9 1-1900 26 •6750 75 •0680 10 1-2066 28 •7340 80 1-0756 11 1-2230 30 1-7860 85 1-0830 12 1-2390 32 1-8220 90 1-0910 13 1-2560 34 1-8376 95 1-0980 14 1-2720 36 1-8426 100 Percentage of Hydrochloric Acid in Aqueous Solutions of Various Specific Gravities. Temp. 15°. Specific Gravity HCl. p.c. Specific Gravity HCl. c.p. Specific Gravity HCl. p.c. 1-0020 0-408 1-0637 13-049 1-1802 36-292 1-0040 0-816 1-0738 15-087 1-1846 37-108 1-0060 1-124 1-0818 16-718 1-1857 i 37-516 1-0100 2-039 1-0899 18-349 1-1875 i 37-923 1-0140 2-854 1-1000 20-388 1-1893 i 38-330 1-0180 3-670 1-1143 23-242 1-1910 38-738 1-0220 4-486 1-1287 26-098 1-1928 39-146 1-0279 5-709 1-1410 28-544 1-1946 39-554 1-0337 6-932 1-1515 30-582 1-1964 39-961 1-0397 8-155 1-1641 33-029 1-1982 40-369 1-0457 9-379 1-1741 35-068 1-2000 40-777 1-0557 11-418 ATOMIC WEIGHTS OF ELEMENTS. 703 Atomic Weights of the Elements.1 Name Symbol Atomic Weight Name Symbol Atomic Weight Aluminium Al 27-01 Molybdenum. Mo 95-53 Antimony Sb 119-95 Nickel. Ni 57-93 Arsenic. As 74-92 Nitrogen. N 14-02 Barium. Ba 136-76 Osmium. Os 198-49 Bismuth. Boron Bi Bo 207-52 10-94 Oxygen. Palladium O Pd 15-963 105-73 Bromine. Br 79-77 Phosphorus. P 30-96 Cadmium Cd 111-83 Platinum Ft 194-41 Caesium. Cs 132-58 Potassium K 39-02 Calcium. Ca 39-99 Ehodium Eh 104-05 Carbon. C 11-97 Eubidium Eb 85-25 Cerium. Ce 140-42 Euthenium Eu 104-22 Chlorine. Cl 35-37 Samarium Sm 149-80 Chromium Cr 52-01 Scandium Sc 43-98 Cobalt. Co 58-88 Selenium Se 78-79 Columbium Nb 93-81 Silicon. Si 28-19 Copper. Cu 63-17 Silver. Ag 107-67 Didymium Di 142-12 Sodium. Na 22-99 Erbium. Er 165-89 Strontium Sr 87-37 Fluorine. F 18-98 Sulphur. S 31-98 Gallium. Ga 68-85 Tantalum Ta 182-14 Glucinum Gl 9-08 Tellurium Te 127-96 Gold Au 196-15 Thallium Tl 203-71 Hydrogen H 1-00 Thorium. Th 233-41 Indium .. In 113-39 Tin ... Sn 117-69 Iodine I 126-55 Titanium Ti 47-98 Iridium. Ir 192-65 ! Tungsten W 183-61 Iron Fe 55-91 Uranium U 238-48 Lanthanum. La 138-02 Vanadium V 51-25 Lead Pb 206-47 ! Ytterbium Yb 172-76 Lithium. Li 7-01 Yttrium. Yt 88-90 Magnesium Mg 23-96 Zinc Zn 64-90 Manganese Mn 53-90 Zirconium Zr 89-36 Mercury. Hg 199-71 F. W. Clarke, Chemical News, vol. 1. p. 89. INDEX ABE ABEL, Sir F. ALK Alkalies and iron, new methods of estimating volmnetrically, 142 — from silicates not soluble in acids, separation of the, 28 — in fire clays, 40 — separation of, for qualitative and quantitative determination, 36 Alkalimetric indicators, new, 654, 677 Alkaline earths, separation of gal- lium from, 127 Allen, A. H,, distinction between phosphates and arseniates, 498 — estimation of iron protoxide, 135 • of tin binoxide, 402 — tests for cobalt, 252 Allen, 0. 707 AQU Aqueous vapour, estimation of, 649 Arable soils, estimation of clay in, 634 Arnold, A. E., assay of tin ores, 406 Arnold,- J. 0., estimation of chro- mium in iron and steel, 216 Arnot, M., decolourising power of animal charcoal, 584 Arseniates and phosphates, distinc- tion between, 498 Arsenic, detection of, 415 — estimation as magnesium pyro- arseniate, 421 — estimation in pentasulphide, 423 — estimations, 423 — from antimony, separation of, 425 — from copper, separation of, 428 — from gallium, separation of, 421 — from tin, separation of, 424 — in bismuth, 428 — in copper, detection of, 430, 431 - in hydrochloric acid, detection of, 420, 576 — in ores, estimation of, 423 — in phosphorus, detection of, 497 — in sulphur, estimation of, 432 — in tartar emetic, 427 — purification of metallic, 415 - - Keinch's test for, 418 — separations of, 421 — tersulphide, estimation as, 423 Arsenical and antimonial com- pounds, solution of, 425 Arsenious acid, estimation of, 419 — — identification of, 418 Asbestos filters, 675 Ashes, detection of manganese in, 237 Assay of Baker guano, 527 — of bleaching powder, 573 of coal before the blowpipe, 604 — of copper pyrites, 310 — of galena in the wet way, 350 - of iron and aluminium phos- phates, 538 — of mercury ores, 293 — of silver ores, 292 — of tin ores, 403 Atomic weights of the elements, 703 Attarberg, A., estimation of phos- phoric acid, 520 Aubel, C., estimation of copper sub- chloride, 326 Avery, C. BLO Blowpipe assay of silver-lead, 357 — detection of bismuth, 389 — of thallium by, 379 Blunt, Mr., analysis of red lead, 366 — detection of nitric acid, 544 Bobierre, M. A., modification of Mohr's method for the assay of iodine, 559 Boettger, E., detection of vanadium in iron ores, 111 Bong, G., decomposition of silicates by lead oxide, 628 Boracic acid, estimation of, 622 Borates and fluoborates, analysis of, 623 Boron, detection of, 621 Boussingault, M., analysis of iron, 146 Brass, &c., estimation of copper in, 300 Braun's test for nitrous acid, 552 Britton, J. B., colorimeter, 157 — colorimetric estimation of carbon in iron, 155 — volumetric valuation of chrome - iron ore, 224 Bromeis, M., estimation of carbon in iron and steel, 143 Bromide of potassium, detection of chloride in, 569 Bromides, detection in presence of chlorides, 569 - of, 564 Bromine and iodine, detection and estimation of chlorine in presence of, 572 in presence of chlorine, esti- mation of, 565 — detection of, 564 — &c., detection in organic matter, 565 — solution of, as a reagent, 565 Brown, T. 