. 1 825.] Dr, Thomson^s Plrst Principks of Chemistri/. 145 



oxides of a metal exist, the oxide which contains least oxygen is 

 admitted to consist of one atom of each of its elements; and 

 that which contains double, of two atoms of oxygen and one 

 of base. By the method which Dr. Thomson has adopted, 

 we have also the anomaly of a protoxide represented by a 

 higher number than a peroxide. Thus while protoxide of 

 •mercury is represented by 208, and the peroxide by 216, the 

 protoxide of copper is 72, and the peroxide 40. 



It was our intention to have offered some observations respect- 

 ing the number by which Dr. Thomson repuesents alumina, but 

 we have extended this article to so considerable a length, that 

 we have room only for one quotation more, and is that which 

 forms the conclusion of Dr. Thomson^s work, respecting an 

 empirical law of Berzehus. 



" Before concluding these general observations,'* observes 

 l)r. T. " I may say a few words respecting Berzelius' law, that 

 * in all salts the atoms of oxygen in the ncid constitute a multi- 

 ple by a whole number of the atoms of oxygen in the base/ 

 This law was founded upon the first set of exact analyses of 

 neutral salts which Berzelius made. Now, as neutral salts in 

 general are combinations of an atom of a protoxide with an atom 

 of an acid, it is obvious that the atotns of oxygen in the acid 

 must in all such salts be multiples of the atom of oxygen in the 

 base ; because every whole number is a multiple of unity. Neu- 

 tral salts, therefore, are not the kind of salts by means of whicli 

 the precision of this supposed law can be put to the test. 



^' Even in the subsalts^ composed of 1 atom of acid united to 

 2 atoms of base, it i^ obvious enough, that the law will hold 

 whenever the acid combined with the base happens to contain 

 2 or 4, or any even number of atoms; because all even numbers 

 are multiples of 2^* ,Np,w, tfeis. is .tfi.^^.casa with the following 

 acids: ■■:<i^r/vi: U-i,i-:>):^.ny..v^j^ri^-: 



Phosphoric?!^' T'^Mtrous,' Antiii^^ Citric, 



Carbonic^" ^^^'■Vl^tanic,' Manganesic, Saclactic, - 



Boracic, j'^ ''', ' ,, Arsenious, Molybdous, Chromous^ . 

 Sulphut<lai.5^f^'Sel£rii(^'^ /^^^'^ffi^ ' < f ■ V . ; 



;G6iis^ueh%V''tfe1aw^rffuk'^K6rd |6o<f 'tif ^#dlWi?l^om>4f 

 Vktom of these acids with 2 atoms of ba§e.-^'^':^^^'5X9 .i:K'i|:'^r 

 -' "In thfe case of all those acids which cdntain oViiy 1 atorn of 

 Wiygen, all the subsalts composed of 1 atom of the acid united 



-'to 2 atoms of base, the law will also in some sort hold ; for the 

 ^ibihs of the oxygen in such acids being 1, this numbercx<^Sil 



^yays be a submultiple of 2, the number of atoms of o5irw^» in 



.platoms of base. This is the case with the Mlomn^uti^P^'i^ 



-11^^ ««y Silicic, .^a sidi?. Hyposulphuroii^ 'jo p.^ha sds 



:jaiifim Pl>Osphorous,:aiia £ 8f^>^P^i^ <if:tetoi^9arit»!^>nt 



