134 Dr. Thomson's Experiments to determine the [Aug. 



than one per cent. Now in an experiment consisting of three 

 solutions, three evaporations to dryness, and three nitrations, I 

 hold it beyond our present skill to guarantee a nearer approach 

 to the truth than one per cent. This experiment then amounts 

 to as complete a verification of the composition of borax as I am 

 capable of exhibiting. 



5. Borax appearing, from the preceding analysis, to be a 

 compound of one atom of boracic' acid and two atoms of soda, I 

 was desirous to see what effect the addition of another atom of 

 horacic acid would have upon the properties of this salt. I dis- 

 solved 19*75 grs. of it in hot water, and added 2*75 grains of 

 glassy boracic acid. After the solution was completed, the 

 liquid produced exactly the same effect upon cudbear paper that 

 borax itself does. Another addition of 2*75 grs. of anhydrous 

 boracic acid did not alter this property ; nor was the property 

 impaired by the addition of a third 2*75 grains ; yet this solution 

 must have contained 4 atoms of boracic acid =11 grs. and only 

 2 atoms = 8 grs. of soda. We see from this that boracic acid 

 does not possess the property of neutralising soda. Upon set- 

 ting aside this solution in an open vessel, it gradually evaporated 

 to dryness, but no appearance of any thing like regular crystals 

 could be observed. 



These experiments on boracic acid are the most accurate 

 which 1 have been able to make. 1 have selected them out of a 

 great number which do not offer better results than those which 

 1 have given, and which, therefore, I thought it unnecessary to 

 transcribe. Though they do not absolutely decide the point, yet 

 they render it exceedingly probable that an atom of boracic acid 

 weighs 2* 75, or exactly the same with carbonic acid. Borax, 

 then and carbon have the same atomic weight each, or 0'75 ; and 

 horacic acid, like carbonic, is a compound of one atom boron + 

 two atoms oxygen. 



VII. Oxalic Acid. 



Berzelius considers oxalic acid as a compound of 1 atom 

 hydrogen + 12 atoms carbon + 18 atoms oxygen. According 

 to this notion, an integrant particle of it should weigh 27*125. 

 The number which he assigns, viz. 27*106, owes its slight differ- 

 ence from 27*125 to the weights which Berzelius has given to 

 the atoms of carbon and hydrogen not being quite the same as 

 mine. Carbon, according to him, weighs 0*7533 ; while hydro- 

 gen weighs only 0*062177. But when we come to examine the 

 saline combinations of oxalic acid, we find that a much smaller 

 weight of it than 27*125 is able to saturate an atom of each of 

 the bases. Oxalate of potash, according to the statement of 

 Berzelius himself, is composed of 



Acid 43*37 or 4*595 



Potash 56*63 6*0 



100*00 



