188 Extracts from Berzelius's Annual Report for 1843. 



simple bodies. M. Pelouze (Pogg. Ann. LVIII, 171) has also exam- 

 ined this question. He has followed a new method, and has arrived at 

 a result which would seem to put an end to this discussion. To accom- 

 plish this, it is only necessary to perform a single experiment requiring 

 two weighings. This experiment consists in decomposing the chlorate 

 of potash, entirely free from water, in a convenient vessel. This salt 

 is composed as we all know of one atom of potassium, two atoms of 

 chlorine and six atoms of oxygen. The six atoms of oxygen are 

 driven off by heat, and one atom of chloride of potassium is left. The 

 weight of the six atoms of oxygen, according to the hypothesis, is 

 equal to forty eight equivalents of hydrogen, consequently the weight 

 of the chloride of potassium which remains ought to be exactly divisi- 

 ble by the weight of the equivalent of hydrogen, if the atomic weights 

 of chlorine and potassium are equal to entire multiples of the equiva- 

 lent of hydrogen. M. Pelouze has obtained from three experiments 

 upon one hundred parts of the chlorate of potash. 



Oxygen gas, 39-157 39143 39-161 



Chloride of potassium, 60-843 60-857 60-839 



These numbers accord with those of M. DeMarignac and of Ber- 

 zelius. 



M. B. 



Oxygen gas, 39-161 39150 



Chloride of potassium, 60-839 60-850 



M. Pelouze has deduced from these results 932-295 as the atomic 

 weight of the chloride of potassium, and if this divided by 12-5, which 

 is the equivalent of hydrogen from the experiments of Dumas, we ob- 

 tain 74-583 equivalents of hydrogen ; a result which differs from the 

 hypothesis by too large a number to be due to an error of analysis. 



Atomic Weight of Hydrogen. — M. Berzelius reviews at some length 

 the experiments of M. Dumas upon this subject, who thinks that he has 

 established the equivalent of hydrogen to be 12-5, oxygen being 100. 

 Berzelius seems to think that the method of experimenting was not 

 free from error. 



Atomic Weight of Chlorine. — The authors of the revision of the 

 atomic weights have also made some experiments upon the equivalent 

 of chlorine. The opinions of M. Dumas determined M. Marignac to 

 make a series of experiments, which he communicated to the Acade- 

 mic des Sciences, April, 1842. The result of the calculation from 

 these experiments, pointed out 450 as the equivalent of chlorine, or 

 thirty-six times the equivalent of hydrogen. M. Laurent (Comptes 

 Rend us, XIV, 570) communicated about the same time a research 

 upon the same subject. He analyzed the substance obtained by treat- 

 ing the chloride of naphthaline (C^°H^-|-4C1) by an additional quantity 



