294 



Mr. Griffin on the Constitution of 



as each degree measures the 10,000th part of an imperial 

 gallon, it is easy to find the relation between the chemical 

 strength and the physical mass of a given solution. 



Methods of Experimenting. 



The experiments that are distinguished in the following 

 Tables by the letter G were made in my laboratory, except 

 in those cases where other authorities are specified. The 

 chemical solutions were ' prepared in stoppered graduated 

 glasses at the temperature of G2° F. The requisite analyses 

 were all effected by the method of centigrade testing. Various 

 precautions were taken to ensure accuracy, but I forbear to 

 enter into details, because they would occupy too much space, 

 and I reserve them for a separate work on Centigrade Test- 

 ing, which I purpose to publish for the use of chemical 

 manufacturers. The specific gravities were determined by 

 weighing the solutions in light bottles, of which three sizes 

 were used, capable of containing respectively 3000, 700, and 

 350 grs. of water. The balance in which the large bottle was 

 weighed turned with half a grain when loaded. That in 

 which the small bottles were weighed turned with "01 gr. 

 when loaded. The weighings were all taken when the liquors 

 were at the temperature of 62° F. The greater part of the 

 experiments were made by my assistant, Mr. Joseph White 

 of Nottingham ; the others by myself. 



The tables of mineral acids were calculated from the ex- 

 periments already published by Dr. Ure and other chemists. 



Atomic Volume of Water. 

 For the sake of subsequent reference I shall state the atomic 

 Volume of water, as derived from the atomic weights both of 

 Dumas and of Berzelius. 



Table I. — Water. 

 H a O = 112-48 grs. : Berzelius. 



m 112*5 grs.: Dumas. 

 Temperature 62° Fahrenheit. 



The last column of this table shows the atomic volume of 

 water, or the bulk of 1 test atom at 62° Fahr., expressed in 

 septems. 



