260 



Dr. Thomas Thomsons Observations 



which sinks helow the mean number 0-375 by 0-012, or 

 about -jL. If we take Berzelius's atomic numbers, the 

 result will be seen in the following table. 



Atoms of 

 Berzelius. 



Specific | 

 heat. 



Product. 



Tellurium, I 8-0176 1 0-0912 0-731 



Bismuth, . . . . • 1 13-30377 0-04 0-532 

 Mercury, I 12-65823 1 0-029 1 0-367 



The reader will perceive, at a glance, that the numbers 

 chosen by Berzelius to represent the atomic weights of 

 tellurium and bismuth cannot be the true numbers. His 

 number for tellurium is almost exactly double mine. Four, 

 there is every reason for believing, is the exact atomic 

 weight of tellurium. Doubtless, there is a small error in 

 the determination of the specific heat. Had the specific 

 heat been 0-0391 instead of 0-0912 the product into the 

 atomic weight would have been 0*375. 



It is equally obvious that 13"3 cannot be the true atomic 

 weight of bismuth. The product of this number by the 

 specific heat of bismuth deviates too far from 0-375 to per- 

 mit us to adopt it. The atomic weight of mercury, as fixed 

 both k by Berzelius and myself, differ very little from each 

 other. If the specific heat be accurately determined both 

 are too low ; 13 in all probability is the correct number. 



Four of these simple bodies, namely, 



Arsenic, . . . 0-385 



Iron, .... 0-385 



Zinc, .... 0-383 



Hydrogen,. . . 0-412 



Mean, .... 0-391 

 have numbers obtained by multiplying the atomic weights 

 into the specific heats higher than 0*375 by about -^d part. 

 Let us compare them with Berzelius's numbers. 



Arsenic, 

 Iron, . 

 Zinc, 

 Hydrogen, 



Atoms of Specific p j t 

 Berzelius. heat. 



4-70042 

 3-39205 

 4-03226 

 0-062398 



0-081 

 0-11 

 0-0927 

 3-2936 



0-381 

 0-373 

 0-374 

 0-205 



