None
Fine iron wire 0.2475 millimetres diameter. 7. Fine iron wire 0.34 millimetres diameter. 8. Ewing and Klassen, " Phil. Trans. Roy. Soc." vol. clxiv. A, p..015. Table 303. MAGNETO-OPTIC ROTATION. Faraday discovered that, when a piece of heavy glass is placed in magnetic field and a beam of plane polarized light passed through it in a direction parallel to the lines of magnetic force, the plane of polarization of the beam is rotated. This was subsequently found to be the case with a large number of substances, but the amount of the rotation was found to depend on the kind of matter and its physical condition, and on the strength of the magnetic field and the wave-length of the polarized light. Verdet's experiments agree fairly well with the formula — B = clH(r-Xp) r l \ dK/K*' where c is a constant depending on the substance used, / the length of the path through the substance, H the intensity of the component of the magnetic field in the direction of the path of the beam, r the index of refraction, and A the wave-length of the light in air. If H be dif- ferent, at different parts of the path, IH is to be taken as the integral of the variation of mag- netic potential between the two ends of the medium. Calling this difference of potential v, we may write B = Av, where A is constant for the same substance, kept under the same physical conditions, when the one kind of light is used. The constant A has been called " Verdet's con- stant," * and a number of values of it are given in Tables 303-310. For variation with tempera- ture the following formula is given by Bichat : — R = j? (1 — 0.00104? — O.OOOOI4* 2 ), which has been used to reduce some of the results given in the table to the temperature corre- sponding to a given measured density. For change of wave-length the following approximate formula, given by Verdet and Becquerel, may be used : — » 1 _ /» 1 1 V-i)V where fi is index of refraction and A wave-length of light. A large number of measurements of what has been called molecular rotation have been made, particularly for organic substances. These numbers are not given in the table, but numbers proportional to molecular rotation may be derived from Verdet's constant by multiplying in the ratio of the molecular weight to the density. The densities and chemical formula are given in the table. In the case of solutions, it has been usual to assume that the total rotation is simply the algebraic sum of the rotations which would be given by the solvent and dissolved substance or substances, separately; and hence that determinations of the rotary power of the solvent medium and of the solution enable the rotary power of the dissolved substance to be calculated. Experiments by Quincke and others do not support this view, as very different results are obtained from different degrees of saturation and from different solvent media. No results thus calculated have been given in the table, but the qualitative result, as to the sign of the rotation produced by a salt, may be inferred from the table. For example, if a solution of a salt in water gives Verdet's constant less than 0.0130 at 20° C, Verdet's constant for the salt is negative. The table has been for the most part compiled from the experiments of Verdet and H Becaue,  52. "Ann. de Chim. et de Phys." [3] vol. 12; "C. R. vols. 90 and 10a § Wied. Ann." vol. 24. "Wied. Ann." vol. 26. "Wied. Ann." vol. 24. "Wied. Ann." vol. 24. "Zeits. for Phys. Chem." vol. n. "Proc. Roy. Soc." 1883. "Phil. Trans. R. S." 1883. "Phil. Trans. R. S." 1883. "Phil. Trans. R. S." 1883. "Phil. Trans. C. "Authority." Amber - - O.OO95 18-20° Quincke. Blende ZnS -  B.... 4.284 O.0649 O.0649 O.0325  it Spinel (colored by chrome). Sylvine KC1 - tt tt tt Ziqueline (suboxide of copper) Cu 2 B 0.5908 Smithsonian Tables. 285 v\ Table 304. MAGNETO-OPTIC ROTATION. Liquids. Substance. Chemical formula. Density in grammes per c. c. Kind of light. Verde's constant in minutes. Temp. C. Authority. C 8 H e O 0-7947 D 0.0113 20 Jahn. it 0-7957 tt 0.0115 15 Schonrock. Acids: (see also  " 0-0343 is Perkin. Hydrochloric. HNOs 1.5190 " O.0030 13 " (fumin g) it tt 0.0080 IS Becquerel. Propionic C8H6O2 0.9975 n O.OIIO is Perkin. Sulphuric H 2 S0 4 - tt O.OI2I 15 Becquerel. Sulphurous Becquerel. Ethyl. C 2 H 5 OH 0.7929 u 0.0107 18-20 Quincke. tt 41 0.7900 " O.0112 20 Jahn. it ti 0.7944 (< 0.01 14 15 Perkin. it it 0.7943 tt 0.01 13 16 Schonrock. Methyl. CH 3 OH o.7915 tt O.0094 18-20 Quincke. a it 0.7920 tt tt O.0096 O.0096 O.0096 IS 21.9 Perkin. Schonrock. Octyl. C 8 Hi 7 OH 0.8296 tt O.0134 is Perkin. Propyl. C s  3 H 7 Br 1.3600 " O.OlSo 15 tt Carbon disulphide CS 2 1.2644 it O.O441 18-20 Quincke. " it O.O434 18-20 Quincke. " it O.O420 18 Rayleigh. it it " ( O.O42O 18 Koepsel. a ti tt O.O42O 18 Koepsel. a  tt 0.0321 O.0164 15 20 a Jahn. Ethylene.. C 2 H 5 C1 C2H4CI2 1.4990 0.9169 I.2589 tt O.0166 O.0138 O.0166 15 6 15 Perkin. Methyl. CH S C1 CH2CI2 C 8 Hi 7 Cl PC1 S C 8 H 7 C1 SiCL, S2CJ2 S11CI4 ZnCl 2 1. 2561 tt O.0164 20 Jahn. Methylene. Octyl; Phosphorus protochloride. Propyl.... Silicon.... 0.8778 0.8922 it tt O.0170 O.0162 O.0271 O.0351 15 15 15 Becquerel. Perkin. Becquerel. Perkin. Sulphur bichloride O.0275 15 Becquerel. Tin bichloride. Zinc bichloride. O.0393 0.0151 15 15 O.0393 0.0151 15 15 Ethyl Methyl Octyl....'. C 2 H 5 I CH 3 I C8H17I 1.9417 2.2832 1-3395 U 0.0296 0.0336 0.0213 0.0271 'S •5 15 IS Perkin. Propyl Nitrates : C8H7I 1.7658 tt Ethyl C 2 H 5 O.N0 2 1.1149 li 0.0091 15 •s IS IS is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is is 1-2157 0.0078 ( Propyl.... C 8 H 7 O.N0 2 1.0622 " 0.0091 tt Trinitrin (nitroglycerine). C 3 H s (N0 8 ) 8 1.5996 « 0.0090 0.0095 0.0084 tt Nitro ethane C 2 H 6 N0 2 1.0552 " tt Nitro methane. CH 8 N0 2 1-1432 tt Nitro propane C 8 H 6 N0 2 I.OIOO it 0.0102 te Perkin. Phosphorus (melted) P 0.1316 33 Becquerel. Sulphur (melted). S 0.0883 114 Toluene.... C7H1J 0.8581 0.0269 28.4 Schonrock. 0.0243 IS Becquerel. Water H 2 0.9992 It 0.0130 15 tt 0.9983 tt 0.0131 15 tt 0.9983 tt 0.0131 20 Jahn. Xylene..... C 8 Hio tt 0.0221 15 Becquerel. <t 0.8746 " 0.0263 27 Schonrock. 1 Smithsonian Tables. 287 Table 305. MACNETO-OPTIC ROTATION. Solutions of Acids and Salts In Water. Substance. Chemical formula. Density, grammes per c. c. Kind of light. Verdet's constant in minute! Temp. Authority. C 8 H e O 0-97IS D O.OI29 20° Jahn. Acids : Hydrobromic HBr I.7859 a 0-0343 15 Perkin. ". ti 1. 61 04 (t 0.0304 tt " 1-3775 tt 0.0244 " it. *' 1.2039 it O.O194 « tt " . .. " 1.1163 " O.O168 tt it Hydrochloric HC1 1.2072 « O.0225 tt it " * .. tt 1.1856 tt O.0219 It tt . .. ** I-I573 tt O.0204 tt tt. " 1.1279 " O.OI93 ti " " H 1.0762 it O.0168 " « • ti 10323 tt 0.0150 20 Jahn. U 1.0158 it 0.0140 « tt Hydriodic . . .. HI 1-9473 it O.0513 a Perkirl. " 1.9057 tt O.0499 (( it " 1.8229 it O.0468 " tt . . .. " 1.7007 " O.O421 it it " 1.4495 « O.0323 tt it " 1.2966 tt O.0258 tt tt .... " 1. 1760 tt O.0205 ft tt Nitric HN0 8 1.5190 tt 0.00 10 tt tt "..... it 1.3560 tt 0.0105 O.OI2I 0.0153 « it Sulphuric + 3H2O Ammonia .... Bromides : h 2 so 4 NH 8 0.8918 tt tt tt 15 Becquerel. Perkin. Ammonium .... NH 4 Br 1.2805 tt 0.0226 tt it " .... tt 1. 1576 tt 0.0186 tt tt Barium .... BaBr 2 1-5399 it 0.0215 20 Jahn. Cadmium .... CdBr 2 1.2855 1.3291 tt tt 0.0176 0.0192 tt it a tt " 1. 1608 tt 0.0162 tt a Calcium .... CaBr2 1. 2491 tt 0.0189 tt it Potassium .... KBr lr 337 1. 1424 tt 0.0164 0.0163 it tt Sodium .... Strontium... SrBr 2 1.0824 1. 2901 tt 0.0152 0.0186 it Strontium.... SrBr 2 1.1416 1. 1906 tt 0.0159 0.0140 0.0140 0.0137 (( 20 tt a " " sodium- Chlorides : Na2C0 8 tt 1.1006 1.0564 tt (( it tt Ammonium (sal ammoniac) Barium.... NH4CI BaCI 2 1.0718 1.2897 tt 0.0178 0.0168 IS 20 Verde. Jahn. Cadmium.... CdCl 2 I-I338 !-3i79 tt tt 0.0149 0.0185 tt tt <i 1.2755 it 0.0179 tt Calcium.... tt CaCl 2 II 53i 1. 1504 tt tt O.OT57 0.0165 tt tt a It 1.0832 0.0152 tt tt 0.0152 0.0221 16  Nickel. NiCI 2 1.4685 " O.0270 15 Becquerel. it (c 1.2432 11 0.0196 it u tt (( 1-1233 it O.0I02 It tt " tt 1.0690 it O.OI46 it tt Potassium KCl 1.6000 " O.O163 tt ti t* (I 1.0732 it O.OI48 20 Jahn. tt (( 1.0418 it O.OI44 u a Sodium NaCl 1. 2051 " O.O180 15 Becquerel. tt rt 1. 1058 it 0.01 55 tt " tt W 1.0546 tt 0.0144 il ti tt it 1.0817 it 0.0154 20 Jahn. tt it 1.0418 tt 0.0144 tt a Strontium SrCl 2 CI 1.1921 1.0877 it ti 0.0162 0.0146 it ti u Tin. SnCl 2 1.3280 tt 0.0266 15 Verdet. tt 1.1637 tt 0.0198 (( tt If tl 1.1112 " 0.0175 (( " Zinc ZnCl 2 1.2851 it 0.0196 (( tt tt Chromate of p otass ium. 11 K 2 Cr0 4 1.1 595 i.35g it tt 0.0161 0.0098 0.0126 " Bichromate of " K 2 Cr 2 Oj 1.0786 " Cyanide of mercury tt tt » Hy(CN) 2 it 1.0638 1.0425 0.0136 0.0134 16 it Schonrock. it tt t* » (( 1.0605 It 0.0135 " Iodides : Ammonium. NHJ 1.5948 It 0.0396 0.0386 i <t 5 Perkin. 11 tt 1.5688 " tt tt 1.5109 tl 0.0358 " tt tt 1-2341 It 0.0235 Cadmium Cdl it 1.5156 1.2770 It 0.0291 0.0215 20 tt Jahn. tt Potassium tt KI tt 1.1521 1.6743 I-3398 tl It It 0.0177 0.0338 0.0237 15 11 Becquerel. tt tt 1-1705 (( 0.0182 ti It 1.0871 tl 0.0152 » tt 1.2380 " 0.021 1 20 Jahn. tt tt 1.1245 tl 0.0174 Sodium tt Nal i-i939 1.1 191 tt 0.0200 0.0175 tt ti Smithsonian Tables. 289 Tables 305-307. MAGNETO-OPTIC ROTATION. TABLE 30S. — Solutions ol Acids and Salts In Water. Verdet's Substance. Chemical formula. Density, grammes perc. c. Kind of light. constant . m minutes. Temp. C. Authority. Nitrates : Ammonium NH 4 N0 8 I.2803 D O.OI 21 is Perkin. Jahn. Potassium. KNOs I.0634 O.OI30 20 NaNOs I.III2 O.OI31 Uranium UaOa-NaOs 2.0267 tt O.OO53 11 Becquerel. i< it 1.7640 O.OO78 " « tt ti 1.3865 1.1963 tt it O.OI05 0.01 1 5 a » Sulphates : Ammonium (NH 4 ) 2 S0 4 1.2286 tt 0.0140 is Perkin. " (acid) NH4.HSO4 1.4417 0.0085 Barium BaS0 4 1. 1788 0.0134 20 Jahn. (c tt 1.0938 " 0.0133 Cadmium CdS0 4 1. 1762 0.0139 " tt " 1.0890 0.0136 " Lithium tt LJ2SO4 tt 1. 1762 1.0942 it 0.0137 0.0135 0.01 38 it tt Manganese MnS0 4 1.2441 it 1.1416 il 0.0136 Potassium K2SO4 1.0475 0.0133 " Sodium NaSQ 4 1. 0661 0.0135 TABLE 306. — Solutions of Salts ln Alcohol. — ^_ Substance. Chemical formula. Density, grammes per c. c. Kind of light. Verdet's constant in minutes. Temp. C. Authority. Cadmium bromide. u tt Calcium " tt <( Strontium " a n Cadmium chloride Strontium " tt a Cadmium iodide tt tt CdBr 2 tt CaBr 2 ft SrBr 2 CdCl 2 SrCl 2 Cdl 2 a I.O446 O.9420 O.9966 O.8846 O.9636 O.8814 O.8303 0-8313 O.8274 I.0988 O.9484 D ft (( a tt tt tt it tt 0.01 59 O.OI40 0.01 54 0.0130 0.0140 0.0126 0.01 18 0.01 18 0.01 17 0.0199 0.01 56 20 u tt it ti  Substance. Chemical formula. Density, grammes per c. c. Kind of light. Verdet's constant in minutes. Temp. a Authority. Antimony trichloride SbCl  in the case of substances like iron, nickel, and cobalt which have a variable magnetic susceptibility, the expression in Verdet's equation, which is constant for substances of constant susceptibility, requires to be divided by the susceptibility to obtain a constant. For this expression, he proposes the name "Kundt's constant." These experiments of Kundt and Du Bois show that it is not the difference of magnetic potential between the two ends of the medium, but the product of the length of the medium and the induction per unit area, which controls the amount of rotation of the beam. Table 309. VERDET'S AND KUNDT'S CONSTANTS. The following short table is quoted from Du Bois' paper. The quantities are stated in c.g. s. measure, measure (radians) being used in the expression of "Verdet's constant and Kundt's constant, circular" Name of substance. Magnetic susceptibility. Verdet's constant. Wave-length of light in cms. Kundt's constant. Number. Authority. Cobalt. Nickel Iron Oxygen: 1 atmo.. Sulphur dioxide Water. Nitric acid Alcohol. Ether. Arsenic chloride Carbon disulphide. Faraday's glass 0.0126 Xio -6 — 0.0541 — 0.0633 — 0.0541 — 0.0876 — 0.0716 — 0.0982 — 0.0716 — 0.307 — 0.330 0.315 1.222 1.222 1.738 Becquerel. Arons Becquerel. De la Rive. Becquerel. Rayleigh. Becquerel. 6.44 X J 6.56 5.89 3-99 2.63 0.014 — 4.00 - 5-6 -5-1 -5-8 —14-9 — 17.1 —17.7 Smithsonian Tables. 29I Table 310. MAGNETIC SUSCEPTIBILITY OF LIQUIDS AND CASES. The following table gives a comparison by Du Bois of his own and some other determinations of the iridium susceptibility of a few standard substances. Verdet's and Kundt's constants are in radians for the sodium line JJ. Substance. Verdet's  disulphide Oxygen at 1 atmosphere Air at 1 atmosphere 3-30 3-15 12.22 0.00179" 0.00194" —O.69 —O.57 —O.54 —O.72 0.13 O.024 —O.63 —O.49  shown that the rotation of the major axis of vibration of radiations normally reflected from a magnet is algebraically equal to the normal component of magnetization multiplied into a constant K. He calls this constant, K, Kerr's constant for the magnetized substance forming the magnet. Color of light Spectrum line. Wave-length in cms. Xio» Kerr's constant in minutes per c. g. s. unit of magnetization. Cobalt. Nickel. Iron. Magnetite. Red. Li a 67.7  "Phil. Mag." vol. 29. 292 Tables 312, 313. EFFECT OF MAGNETIC FIELD ON THE ELECTRIC RESISTANCE OF BISMUTH. TABLE 312. -Resistance One Ohm for Zero Field and Various Temperatures. The oscillations, re-filling the atmosphere, the current which conveyed the current through the earth, and the earth's atmosphere, are the same as those of the earth's atmosphere. Temp. C.= 0°  7000 80OO 9OOO I OOOO 15000 20000 25OOO 1. 000 1.018 1.045 I.088 I.I35 I.185 I.240 I.304 I-365 I-423 1.480 1-743 1.037 1.057 1.089 1-134 1.198 1.260 1323 1.392 1.458 1-523 1.592 1.946 2.295 2.645 1.072 1. 091 1.118 1. 162 I.2I0 I.265 I.327 I-385 1-453 I.5J5 I-583 1.907 2.243 2.560 1.115 1. 129 I.156 1.198 I.246 I.290 1 -341 1.404 1.460 1.509 1.860 2.148 2.445 1.200 1.217 1.241 I.266 I.302 1-335 1-379 1.428 1.465 1.520 1.562 1.805 2.055 2.320 1-332 I-34I 1-352 1-375 1-397 1.428 1.464 1.500 1-536 1-573 1.610 1.784 1.980 2.157 • Calculated from the results of J. B. Henderson's experiments, " Phil. Mag." vol. 38, p. 488. Smithsonian Tables. 293 Table 314. SPECIFIC HEATS OF VARIOUS SOLIDS AND LIQUIDS.* Solids. Substance. Temperature in degrees C. Specific heat. Authority. Alloys : Bell metal Brass, red " yellow. 80 Cu + 20 Sn 88.7 Cu + 11.3AI German silver Lipowitz alloy : 24.97 Pb -f- IaI 3 Cd -f- 50. + 14.24 Sn ditto Rose's alloy : 27.5 Pb + 48.9 Bi + 23-6 Sn ditto Wood's alloy : 25.85 Pb + 6.99 Cd + 52.43 1473 Sn ditto (fluid) Miscellaneous alloys : 17.5 Sb + 29.9 Bi + 18.7 Zn + 33.9 Sn 37.1 Sb + 62.9 Pb 39.9 Pb + 60.1 Bi ditto (fluid). 63.7 Pb + 36.3 Sn 46.7  Pa = Pagliani. Pn = Pionchon. T = H. Tomlinson. Th = Thomsen. 0.0858 .08991 .08831 .0862 .10432 .09464 .0345 .0426 .0356 .0552 .0352 .0426 .05657 .03880 .03165 .03500 .04073 .04507 .04001 .04504 .05537 .20-.24 .206 .0635 .1128 .2218 •2733 .4408 .4589 .161 .117 .186 .1726 •2143 .19-.20 .1138 .1604 .2542 .2966 .4450 .4670 .310 R L « R L « M S M R a p it R K H W HM RW J&B H W D E = Emo. HM=H. Meyer. K = Kopp. Ma = Marignac. R = Regnault. W = Wachsmuth. * Condensed from more extensive tables given in Landolt and Bomstein's "Phys. Chem. Tab." Smithsonian Tables. 294 Table 314. SPECIFIC HEATS OF VARIOUS SOL H IDS AND LIQUIDS. Substance. Gypsum. Ice India rubber (Para) Marble, white. " gray. Paraffin ( fluid). Quartz ( fluid). Sulphur, crystalline. Vulcanite. Temperature in degrees C. 16-46 —78-O —30-0 —21-1 —100 16-98 23-98 —20-3 19-20 Specific heat. O.259 .4627 5°5 5°7 .481 .2158 .2099 .3768 5251 6939 .622 .712 .2786 3°5 .163 33 12 Authority. K P (( G&T R « R W Pn K AM Liquids. Alcohol, ethyl methyl Benzene Ethyl ether Glycerine Oils, castor " citron " olive " sesame " turpentine Petroleum CuS0 4 + 50H 2 " + 200 H 2 " -f- 200 H 2 NaOH + 5° H 20 " + 100 H 2 NaCl + 10H 2 " + 100 H 2 NaCl + 10H 2 Sea water: density 1.0043. Sea water: density 1.00235 (about normal) "1.0463 — 20 40 5-10 15-10 10 40 15-50 5-4  .6009 •3402 •4233 .5290 .576 •434 ■438 .471 ■387,. .4106 .951 •975 .842 .952 .876 •975 .942 ■983 .791 .978 .980 ■938 •903 References. A M = A. M.Mayer. B = Batelli. D = Dew f- £ & T = Gee & Terry. H & D = De Heen & Deruyts. HW = H.F.Weber. J & B = Joly & Bartoh I-Lorenz. Ln = Luginin. M = Mazotto. P- Person p a = Pa#liani. Pn = Pionchon. RW=R Weber. T = H. Tomlinson. Th = Thomsen. H&D U R E W H W W R Pa Ma « Th E = Emo. H M = H. Meyer. K Kopp. Ma = Marignac. R = Regnault. W = Wachsmuth. Smithsonian Tables. 295 Table 315. SPECIFIC HEAT OF METALS. Metal. Temperature in Specific heat. Metal. Temperature in Specific heat. Aluminium.. 20 0.2135 N Manganese.. 4-97 0.1217 R 100 .2211 Mercury: solid. — 78 to — 40 .03192 ft 200 .2306 "  500 .12988 tt Cadmium... 21 .0551 N M 800 .1484 " 100 .0570 (( a 1000 .16075 tt Palladium 0-100 .0592 V 30O .0617 tt Calcium... 0-100 .1804 B Platinum — 78-20 03037 s Chromium (?) 22-51 .09975 K Cobalt.... 9-97 .10674 R < 0-784 03 6 5 tt 500 .14516 Pn " 0-1000 .204 " a  17 .09244 N « 1600 tt 100 .09422 tt Potassium —78.5-23 .1662 s 200 .09634 tt Silver. 0-100 •OS59 B Gold '.'.'.'. 300 .09846 " u 23 .05498 N 0-100 .0316 V 100 •05663 tt Iridium... 0-100 0-1400 ■0323 .0401 it it " ; 200 300 •05877 .06091 tt tt Iron IS .1091 N " 800 .076 Pn 100 .1151 tt " fluid 907-1100 .0748 it 200 .1249 it Sodium. —79-5-17 .2830 S 300 ■1376 tt it —28-6 ■ z 934 R 500 .17645 Pn Tin . '. — 78-20 .05416 S 700 •3 2 43' " U .05368 L 720-1000 .218 « ti 50 •°5534 u I00O-I200 .19887 <( " ... 75 .05643 .0637 " Lead .... — 78-H .03065 R " fluid. 250-350 p '5 .02993 N <t K 250 •05799 Pn 100 .03108 a tt tt 1 100 .0758 (( 200 •03244 tt Zinc . .. 0-100 •093S •0915 .0951 .0996 .1040 B " fluid . .. Lithium . .. Magnesium .. u 310 360 27-99 ■03556 .04096 .9408 .2456 Sp R L a it n u 18 190 200 300 N it tt 75 .2509 3OO-40O .122 LV References. B = Bunsen. K = Kopp L = Lorenz. LV = Le Verrier. N = Naccari. P = Person. Pn = Pion chon. Pt = Pouillet. R = Regnault. ng. V = Violle. W = Winkelmann. S = Schiiz. Sp = Spri Smithsonian Tables. * Condensed from Landolt and Bornstein's " Phys. Chem. Tab.' 296 INDEX. Absorption of gases by liquids 125 of solar energy by the atmosphere 177 Acceleration, angular and linear, conversion factors for 19, 21 Activity, conversion factors for 19, 21 Aerodynamics; data for the soaring of planes 100 data for wind pressure 108 Agonic lines 117 Air, specific heat of 223 thermometer 228, 229 Alcohol, density of 96-98 vapor pressure of 126, 225 Alloys, electric conductivity of 251-253 electric resistance of 251-253, 256, 257 density of 85 specific heat of 294 strength of 73 thermal conductivity of 197 thermal conductivity of 248, 249 Alternating currents, resistance of wires for 258 Alums, indices of refraction for 180 Angles, conversion factors for 14 Aqueous solutions, boiling-points of 196 vapor, density of 155 pressure of 151-154 Arc spectrum, wave-lengths in 172 Areas, conversion factors for 11 Atmosphere, pressure of vapor in 157 Atomic weights 272 Barometer, correction for capillarity 124 determination of heights by 169 reduction to latitude 45 122, 123 reduction to sea level 121 reduction to standard temperature 120 Battery cells, composition and electromotive force of 246, 247 Bismuth, electric resistance of, in magnetic field 293 Boiling-point, of chemical elements 207 of various inorganic compounds 210 of various organic compounds 212 of water, barometric height corresponding to 171 of water, effect of dissolved salts on 196 B Rrick, strength of British weights and measures, equivalents in metric capacity, conversion factors for 12 Capacity, specific inductive 263-265 Capillarity, of aqueous solutions 128 correction of barometer for 124 of liquids as solidifying-point 129 of soap films 12 9 Capillarity (continued). surface-tension of water and alcohol . . . 128 various liquids 127 Carat, definition of 18 Cells, battery 246, 247 secondary 247 standard 247 Chemical elements, boiling and melting points of 207 Cobalt, Kerr's constants of 291 magnetic properties of 279 Coefficients, isotonic 150 of diffusion 147, 149 of friction 135 of thermal expansion 214-218 of viscosity 137, 146 Color scale, Newton and Reinold and Rucker 130 Combination, heat of 202 Combustion, heat of 201 Compressibility, of gases 79, 81 pf liquids 82 of solids 83 Conducting power of alloys 251-253 Conductivities, molecular 260, 261 of electrolytes 259 thermal 197, 198 Contact, difference of potential 268 Conversion factor, definition of xviii Conversion factors for acceleration, angular . . 18 acceleration, linear 17 activity 19, 21 angles 14 areas 1 1 capacities 12 densities 23 electric deposition 24 electric displacement 25 electric potential 27 electric resistance 23 energy 20, 21 film tension 20, 22 force 17 heat, quantities of 24 intensity of magnetization 26 length n masses 13 moment of inertia 13 moment of momentum 10 momentum 16 magnetic moment 27 magnetization, intensity of 26 magnetization, surface density of 26 power I9> 2I resistance, electric . . . .' 23 stress 19, 22 temperatures 25 tension, film or surface 20 298 INDEX. Conversion (continued). Time, intervals of velocities 1 5 volumes 12 work 20, 21 Critical temperature of gases 200 Crystals, cubic expansion of 216 elastic constants of 78 formulae for elasticity of 77 refractive indices of 187 Cubic expansion, gases 218 liquids 217 solids 216 Cyclic magnetization, dissipation of energy in : 280-283 Declination, magnetic 1 13-1 18 Densities, of air, values of.4/760 162 alcohol 96-98 alloys and other solids 85 aqueous solutions 9° gases 89 liquids 88 mercury 95 metals 86 organic compounds 212 water 92-94 woods 87 Density, conversion factors for 23 Dew-points, table for calculating 158 Diamonds, unit of weight for 13 Dielectric strength 244, 245 Diffusion of gases and vapors 149 liquids and solutions 147 Dilution of solution, contraction due to 134 Dimension formulae (see also Units) xvii Dip, magnetic in Dynamic units, dimension formulae of xvii formulae for conversion of 2 Dynamical equivalent of thermal unit 219 Earth, miscellaneous data concerning 106 Elasticity, moduli of 74-78 Electric conductivity of alloys 251, 252 of metals 255 relation to thermal 271 constants of wires 58-68, 254 displacement 25 potential, conversion factors for 27 resistance, effect of elongation on 258 units, conversion factors for 3 units, dimension formulae xxv Electrochemical equivalents and atomic weights 272 of solutions 259 Electrolytes, conductivities of 259 Electrolytes, conductivities of 259 Electromotive force of battery cells. 299 Indices of refraction for alums (continued). quartz ...186 rock salt _ T 3 2 solutions of salts .... 1^8 T , s ylvine ...".!i82 Inductance, mutual 42 Integrals, elliptic ..'.'.'....'.'.' I3 Intensity, horizontal, of earth's magnetic field 112 total, of earth's magnetic field no Iron, elasticity and strength of 72 hysteresis in 280-283 magnetic properties of 274-283, 292 ""Isotonic coefficients. Jewels, unit of weight for 13 Joule's equivalent 220 Kerr's constant, definition and table of 292 Kilogramme, definition of xvi Kundt's constants 291 definition of 291 Latent heat 204, 206 Least squares, various tables for 35, 37 Legalization of practical electric units xxxiv Length, conversion factors for n Light, velocity of 176-243 rotation of plane of polarized 191 Linear expansion of chemical elements 214 of various substances 215 Liquids, absorption of gases by 125 compressibility and bulk moduli of 82 density of 88 magneto-optic rotation in 286, 287 magnetic susceptibility 292 refractive indices of 189 specific heat of 295 thermal conductivity of 197, 198 thermal expansion of 217 Lowering of freezing-point by salts 192 Magnetic field, effect of, in resistance of bis-muth 293 moment, conversion factors for 27 permeability 274-280 properties of cobalt, manganese steel, magnetite and nickel 279 properties of iron and steel 276 saturation values for steel 279 susceptibility of liquids and gases 292 units, conversion formulas for 3 dimension formulae for xxv Magnetism, conversion factors for surface density 2 ° terrestrial 110-1 IH Magnetization, conversion factors for intensity of • 26 Magnetite, Kerr's constant for 292 magnetic properties of 279 Magnetite, Kerr's constant for 292 magnetic properties of 279 Magneto-optic rotation, general reference to tables of 28 Magneto-optic rotation, general reference to tables of 28 Masses, conversion factors for 13 Materials, strength of 7°-73 Measurement, units of..... Mechanical equivalent of heat. 220 Melting-points of chemical elements 207 of inorganic compounds zoo Melting-points (continued). of mixtures and alloys 211 of organic compounds 212 Mercury, density of 86 electric resistance of 255, 256 index of refraction 181 specific heat of 225 strength of 70 Metals, density of 86 electric resistance of 254-258 specific heat of 296 thermal conductivity of 197 Metals and metallic oxides, indices of refraction for 181 Metre, definition of xvi Metric weights and measures — equivalents in British 5 equivalents in United States 10 Mixtures, freezing 199 Moduli of elasticity 74-78 Molecular conductivities 261, 262 Moments of inertia, conversion factors for 13 Moment of momentum, conversion factor for 16 Momentum, conversion factors for 13 Mutual inductance, table for calculating 42 Neutral points, thermoelectric 249 Newton's rings and scale of colors 130 Nickel, Kerr's constants for 292 magnetic properties of 279 Ohm, various determinations of 262 Osmose and osmotic pressure 150 Pearls, unit of weight for 13 Peltier effect 250 Pendulum, length of seconds 104, 105 Permeability, magnetic 274-280 Photometric standards 176 Planets, miscellaneous data concerning 106 Poisson's ratio 76 Polarized light, rotation of the plane of 191 Potential, contact difference of 268 difference of, between metals in solutions 269 electric, conversion factors for 27 Pound, definition of xvi Power, conversion factors for 19, 21 Practical electrical Pressure, barometric, for different boiling points of water 170, 171 Critical, of gases 200 effect on radiation 236 of aqueous vapor 1 51-1 54 at low temperatures 156 in the atmosphere 1 57 of mercury column 119 osmotic 15° of vapors 126, 225-227 of wind 108 Probability, table for calculating 36 Quartz, fibres, strength of 7° refractive index of 186 Radiation, effect of pressure on 236 Relative humidity 161 3°° INDEX. Resistance (see also Conductivity), electric. of alloys 251-253, 256, 257 of electrolytes 259 of glass and porcelain 270 of metals and metallic wires 254-257 of wires, effect of elongation on 258 Rigidity, modulus defined 74 of metals.., 74 variation of, with temperature 7° Rotation, magneto-optic 284-291 Saturation values, magnetic, for steel 279 Seconds pendulum, length of 104, 105 Secondary batteries 247 Sections of wires 44~54> 58-68 Sheet metal, weight of 56, 57 Soaring of planes, data for 109 Solar constant '77 Solar spectrum, wave-length in 172 Solids, compressibility and bulk moduli of...83 density of 85 magneto-optic rotation in 284 Solution, contraction produced by 131-134 Solutions, aqueous, boiling-points of 196 density of 90 magneto-optic rotation in 288-290 refractive indices for 188 specific heat of 224 Sound, velocity of, in air 99 in gases and liquids 101 in solids 100 Specific electrical resistance, conversion factors for 23, 254-256 Specific gravity (see also Density). of aqueous ethyl alcohol 96 methyl alcohol 97 of gases 89 Specific heat of air 223 of gases and vapors 224 of metals 296 of solids and liquids 294, 295 of water 223 of water, formulae for 222 Specific inductive capacity 263-265 viscosity, aqueous solutions 144 oils 137 water 136 Spectra, wave-lengths in arc and solar 172 Standard cells 247 wave-lengths of light 172 Standards, photometric 176 Steel, physical properties of 71 Steam, properties of saturated 237 Steinmetz, constants for hysteresis of 281 Stone, strength of 70 thermal conductivity of 197 dielectric 244 Strength of materials 70-73 Stress, conversion factors for 19, 22 Surface-tension, constants of 128, 129 conversion factors for 20, 22 Sylvine, refractive index of 182 Temperature, conversion factors for 25 critical, of gases 200 Terrestrial magnetism, agonic lines 117 declination, data for maximum east at various stations 118 dip and its secular variation for different latitudes and longitudes in Terrestrial magnetism {continued). horizontal intensity and its secular variation for different latitudes and longitudes 112 secular variation of declination 1 13-1 16 Thermal conductivities 1 97 relation to electrical 271 expansion, coefficients of 214-218 units, dynamic equivalent of 219 Thermoelectricity 248-250 Thermometer 228-233 air 228, 231 correction of, for mercury in stem 232 hydrogen 231 mercury in glass 229 zero change due to heating 229 zero, change of, with time 230 Timber, strength of 7°, Time, unit of, defined xvii Times, conversion factors for.... 14 Transformers, permeability of iron in 274, 275, 280, 282 Units of measurement xv dimension formulae for dynamic xviii electric and magnetic xxv electromagnetic xxix electrostatic xxvi fundamental 2 heat xxiii practical, legalization of electric xxxiii ratio of electrostatic to electromagnetic 243 United States weights and measures in metric 9 Vapor, density of aqueous 155 diffusion of 149 pressure of 126, 225-227 pressure of aqueous 1 51-154 values of 0.3781? 160 pressure of, for aqueous solutions 194 refractive indices for 190 specific heats of 224 Vaporization, latent heat of 204 Velocity, angular and linear, conversion factors for 15 of light 176, 243 of sound 99, 101 Verdet's constants for alcoholic solution of salts 290 aqueous solutions of salts 287 gases 291 hydrochloric acid solutions of salts 290 liquids and solids 285-287 and Kundt's constants 292 Viscosity, coefficient, definition of 136 coefficient of, for aqueous alcohol 137 for gases 146 for liquids 138 temperature effect on, for liquids 139 specific, for oils 137 for water 136 Volumes, conversion factors for 12 critical, of gases 200 Water, boiling-point for various barometric pressures 170, 171 density of 92-94 specific heat of 222, 223 INDEX. 301 Water (continued). Thermal conductivity of 198 viscosity of 136 Wave-lengths of Fraunhof er lines 175 standard for arc and solar spectrum 172 Weights and measures — British Imperial to Metric 7, 8 Metric to British Imperial 5, 6 Metric to United States 10 United States to Metric 9 Weights of sheet metal 56, 57 Weights of wires 44-54 Wind, pressure of 10 8 Wire, gauges 5 Woods, densities of 0° Work, conversion factors for 20, 21 Yard, definition of xvl Young's modulus 75 modulus, definition of 75 Zonal harmonics 4°. 