26 HISTORICAL INTRODUCTION. 



experiments have been very numerous, amounting 

 to many thousands. At first my progress was 

 very slow ; because I was obliged to try many 

 methods of investigation before I hit upon one 

 sufficiently accurate for my purpose. But I 

 found the subject become easier as I proceeded, 

 and at last I acquired so much facility, that, 

 during the last four months, I have been able 

 to determine with tolerable accuracy the consti- 

 tuents of at least a hundred salts. My first ob- 

 ject was to satisfy myself whether Dr. Prout's 

 opinion, that the atomic weights of all bodies 

 are multiples of that of hydrogen, was correct j 

 because the establishment of its truth would at 

 once give a simplicity to the atomic numbers, 

 which had not been suspected, and would place 

 the science of chemistry in a new and much more 

 advantageous situation than it had ever oc- 

 cupied. The very numerous investigations, 

 which will be exhibited in the following pages, 

 will, I flatter myself, fully establish the truth of 

 Dr. Prout's sagacious conjecture. For every 

 substance, of which I could procure a sufficient 

 quantity to enable me to examine it fully, has 

 been found not only a multiple of the atomic 

 weight of hydrogen ; but, if we except a few 

 compounds into which a single or odd atom of 

 hydrogen enters, they are all multiples of 0-25 

 or of two atoms of hydrogen. 



After determining the atomic weights of all 



