On the Atomic Theory. 25 



been described by Gay Lussac, and contains twice the oxy- 

 gen contained in water. As therefore there are two com- 

 pounds of oxygen with hydrogen, the formula cannot apply. 



Second. — Having obtained the representative numbers of 

 oxygen and hydrogen, if we examine by the same formula, 

 ammonia, which is the only compound known of hydrogen 

 and nitrogen, and if we suppose it to be composed of one 

 atom hydrogen united to one 'atom nitrogen, it gives a num- 

 ber for the latter substance, which is only one third of its real 

 representative value. 



Mr. Dalton carried his rule through the whole system in 

 a rigorous manner, and hence obtained a number for nitro- 

 gen, which has, by all other chemists, been considered as er- 

 roneous. 



Drs.Thomson, Henry,and Wollaston, and Professor Brande, 

 follow the Daltonian formula as it regards water, but, when 

 they arrive at ammonia, finding it will not bend to the hy- 

 pothesis, they lay aside the rule, and consider it as composed 

 of three atoms hydrogen and one atom nitrogen ; because it 

 is composed of three volumes of the former and one of the 

 latter. 



Third. — If water is composed of one atom of each, hy- 

 drogen and oxygen, or, is a binary combination ; it forms an 

 exception to all other known compounds. If we examine 

 the union of metals with each other, with oxygen, with sul- 

 phur, or the acids, we find they are all ternary, or superior 

 combinations ; so also are atmospheric air, and all animal 

 and vegetable substances. 



The union of one atom of each of two substances can 

 be formed, only by great skill and care on the part of the 

 chemist, and is usually effected by abstracting from the high- 

 er combinations a portion of one of its constituent parts. Na- 

 ture forms few binary compounds. 



Fourth. — If we examine a mathematical demonstration 

 of the fact, we shall be led to believe, that, were a number 

 of atoms of two substances placed together without previous 

 arrangement, affinity would be exerted in the highest de- 

 gree, when two atoms, of a similar kind, were arranged on 

 the opposite sides of an intervening atom, and where the 

 line of attraction passed through the centre of each. 



Dr. Bache, in his valuable book on chemistry, has en- 

 deavored to obviate the difficulty, by supposing the combining 

 volume of oxygen, to be onlv half the size of the combining 



Vol. XIV.— No. 1. 4 



