GENERAL OBSERVATIONS. 467 



These, and many other similar relations between 

 the atomic weights of the different bodies, will be 

 obvious by barely inspecting the tables, and 

 need not therefore be pointed out. 



15. Though the seventeenth and eighteenth water of 

 chapters of this work exhibit the composition of Son oftfae 

 307 salts, a greater number than has ever before salt ' 

 been subjected to actual analysis by any indi- 

 vidual, yet they do not enable us to detect any 

 law with respect to the number of atoms of 

 water which exist in the salts in the state of 

 water of crystallization. Of these 307 species 

 of salts, eighty are anhydrous thirty-one contain 

 1 atom of water fifty contain 2 atoms twenty- 

 seven 3 atoms eighteen 4 atoms twelve 5 

 atoms nineteen 6 atoms eighteen 7 atoms 

 ten 8 atoms four 9 atoms ; all of which are 

 compound salts six contain 10 atoms none 

 contain 11 atoms and two contain 12 atoms. 



No simple salt has been met with containing 

 more than 12 atoms, except the sesquinitrate 

 of uranium, which seems to contain 17 atoms. 

 But the compound salts are found with a much 

 greater quantity of water. Thus, one contains 

 16 atoms of water five contain 25 atoms and 

 one contains 55 atoms. Next to the anhydrous 

 salts, by far the most abundant are the salts 

 which contain 2 atoms of water. The salts 

 containing 1, 2, and 3 atoms, added together, 



Gg2 



