396 
PROFESSOR J. W. MALLET ON THE ATOMIC WEIGHT OF GOLD. 
Earlier Determinations of the Atomic Weight of Gold. 
In the work of L. Mulder, ‘ Historisch-kritisch Overzigt van de Bepalingen der 
.^quivalent-Gewigten van 24 Metalen,’ Utrecht, 1853, and in the recent papers of 
Kruss and of Thorpe and Laurie, there are abstracts of reports upon a number of 
experiments by chemists of the earlier part of this century bearing on the value to be 
assigned to the atomic weight of gold, such as those of Proust,* * * § Eichter,! Dalton,| 
Thomson,§ Oberkampe,|| Pelletier,^ Figuier,** * * §§ and jAVAL;tt but of these none 
deserve any attentive consideration at the present day, the methods used having in 
some cases been such that accurate results could not be expected from them, and the 
actual hgures obtained in other cases differing so widely from each other that no 
importance can be attached to them. 
Before the year 1887 but two chemists —Berzelius and Levol— had published the 
results of experiments furnishing fairly admissible data for calculating the atomic 
weight in question. 
A. Experiments qf Berzelius, 1813.;j;|—The method adopted was the precipitation 
of a solution of auric chloride by metallic mercury, determining the quantities of 
mercury dissolved and gold thrown down. In the original paper but a single experi¬ 
ment is reported, but later the author appears to have made a second,§§ so that for the 
two Meyer and Seubert, in them recalculation of the atomic weights of the elements,|||| 
give as the sums of the amounts of mercury and gold found to be equivalent to each 
other 24’240 grm. of the former and 15‘912 grm. of the latter. Taking these quan¬ 
tities to represent the ratio between the weights of three atoms of mercimy and two 
atoms of gold, we have for the weight of the single atom of the latter (H = J) 
If we assume Hg = 199'8 (L. Meyer and Seubert||||). . 19673 
„ „ „ 199712 (F. W. Clarke^). . . . 196-65 
This method recommends itself as advantageous on several grounds, and the 
experiment deserves repetition as soon as the atomic weight of mercury becomes 
* ‘ Journal de Physique,’ vol. 62, 1806, p. 131; ‘ N. Gehlen, Journal,’ vol. 1, 1806, p. 477. 
t ‘ SCHWEIGGEE, Journal,’ vol. 7, 1813, p. 43. 
t ‘ New System,’ part 2, 1810, ji. 253. 
§ ‘ First Principles,’ vol. 1, 1825, p. 440. 
II ‘ Annales de Chimie,’ vol. 80, 1811, p. 140. 
^ ‘ Annales de Chimie,’ vol. 15, 1820, pp. 5, 113. 
** ‘ Annales de Chimie,’ vol. 19, 1821, p. 177. 
tt ‘Annales de Chimie,’ vol. 17, 1821, p. 337; ‘ ScHWEiGGER, Journal,’ vol. 33, 1821, p. 238. 
tt ‘ Stockholm, Kgl. Vetensk. Akad. Handl.,’ 1813, p. 185. 
§§ Berzelius, ‘ Lehrbuch,’ vol. 3, p. 1212, sti-. 70. 
111! Lothae Meter u. KArl Seubert, ‘ Die Atomgewichte d. Elemente aus d. Originalzahlen 
berechnet,’ Leipzig, 1883, p. 191. 
“ The Constants of Nature,” ‘ Smithsonian Miscellaneous Collections,’ Washington, D.C. 
