2^ ON OXALIC ACin. 



no c4idrcoal at all remains. Hence it probably acts upon tlie 



carbonic acid united to the base, converting; it into carbonic 



oxide, as happens when a mixture of a Ci^rbojate and diur- 



coal are healed. 



Decomposition 3. I was induced to examine this decomposition with con- 



of oxalate of si(jprab!e attention, because 1 conceived, that it would fur- 



lim;; altdiitive- « • • ■ • • p i- • i 



ly examined, nish the means of estimatmg the composition ot oxalic acid ; 



and I pitched upon oxalate of lime, as the salt best adapted 

 for the purpose I had in vie^v. A determinate quantity of 

 this salt was put into a small retort, 'and gradually heated 

 to redneiis. This retort was connected with a pneumatic 

 trough by means of a long glass tube, having a valve at its 

 extremity, which allowed gas to issue out, but prevented 

 any water from entering the tube. The experiment was re- 

 peated three times. 

 TOO grs. yield 4. A hundred grains of oxalate of lime, when thus heated, 

 Jys^"*^'^ ° yield above sixty cubic inches of a gas, which is always a 

 mixture of carbonic acid and iidiammable air, nearly in 

 the proportion of one part of the former to three and a half 

 of the latter, reckoning by bulk. The specific gravity of 

 the inflammable gas was 09O8, common air being roOO; 

 it burns with a blue flame, and, when mixed with o.vigen, 

 may be kindled by the electric spark. The loudness of the 

 report depends upon the proportion of oxigen. 

 Mixed wih The smallest quantity of oxigen, with whi(;h it can be- 

 dlelT' the '"" ™'^*^<^j SO as to burn by the electric spark, is J-th ; the coth- 

 electric spark, bustion is very feeble, and is attended with no perceptible 

 report. If the residue be washed in lime water, and mixed 

 with i^th of its bulk of oxigen, it may be kindled a second 

 time : this may be repeated live times, after which the resi- 

 due cannot be made to burn. 



The combustion becomes more violent, and the report 

 louder, as we increase the proportion of oxigen, and both 

 are greatest when the oxigen is double the bulk of the gas. 

 As we increase the dose of oxigen, the combustion becomes 

 more and more feeble; and five parts of oxigen and one of 

 gas form the limit of combustion on this side: for a mixture 

 of six parts of oxigen and one of the inflammable air will not 

 burn. 



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