350 Analysis of Scientific Booh. 



" The result of the other experiments on oxalate of lime were 

 nearly the same as the preceding. The following may be stated 

 in round numbers, as the mean of the whole : 



Oxalic acid is a compound of Oxygen 64 

 Carbon 32 

 Hydrogen 4 



100*" 

 We shall now shew that more errors are crowded into the 

 above concluding statement of the Doctor's paper, than are to 

 be found in any dozen volumes of the Royal Society's Trans- 

 actions besides. It is now known from the concurring results 

 of Dulong, Berzelius, and Dobereiner, to which some decisive 

 ones obtained in this country will soon be added, that oxalic 

 acid, such as it exists in oxalate of lead, contains no hydrogen t- 

 Now as Dr. Thomson's contained 4 per cent, of hydrogen, we 

 must allow it 32 of oxygen, being the quantity equivalent to its 

 •aturation, and of course 36 per cent, of water is the inevitable 

 result — a quantity actually greater than the Reviewer assigned. 

 Though he says in his answer, " No water existed in the acid as I 

 employed it," yet we find in the very memoir under discussion 

 11^ per cent, of water ope?iZ?/ stated. Butoxalateof limeis by no- 

 means necessarily an anhydrous compound. " L'oxalate de 

 chaux," says Berzelius in his late memoir, " pent se combiner 

 avec de I'eau en deux proportions, dont I'une est Ca O- +2 aq. 

 and the other C a O^ + 4 ag . , et le plus souvent on les obtient 

 melees ensemblej." 



The above anhydrous oxalate is 8.0, to which adding 2 

 atoms water = 2.25, we have the sum 10.25; whence such a 

 ■alt contains in 100 parts 22 of water. Thomson's contained 4 of 

 hydrogen, along with its saturating quantity of oxygen, constitut- 

 ing a sum = 36 per cent. Now this is exactly the quantity corre- 

 sponding to 4 atoms of water ; for 8 oxalate + 4.5 water zz 12.5, 

 and 12.5 : 4.5 :*, 100 : 36. Now taking away these 36 parts of 

 water, or 4 hydrogen and 32 oxygen, certainly foreign to the 

 constitution of real oxalic acid, we have a remainder of 32 car- 

 bon, and 32 oxygen, for its composition as given in the above blun- 

 dering memoir. This proportion transferred to atomic numbers is 

 3 atoms of oxygen to 4 atoms of carbon ; whereas its true compo- 

 sition is 3atoms of oxygen to 2 atoms of carbon. Sxich washisnear 

 approach to truth, or rather such was his affinity to error i?i these 

 experiments ! He makes the proportion per cent, of carbon to be 

 50, while it is only 33.3. " Now it is clear," said he, " that 89 

 grains of oxalate of lime, well dried, were composed of lime 

 33.4, acid 55.Q." From the sixth edition of his System, " it is 

 clear" that 89 grains of well-dried oxalate of lime are composed 

 of lime 39 . acid 61. For 8.0 : 3.5 :: 89 : 39; or rather 



* Phil. Trans, for I807, p. 63. 

 ■f See Berzelius'js paper on the muriates of platinum and gold. Annales 

 d» Chimie et de Phytique, Oct. 18-21. J Ibid. p. 156. 



