510 



Messrs. Playfair and Joule otto^K 



- The Volumes of the oxalates can only be explained by ajof 

 attentive consideration of the previous results. We have 

 already seen numerous instances in which the primitive vo- 

 lumes 9*8 and 11*0 become mutually convertible ; this is stri- 

 kingly the case with the salts of the present section. Hydrated 

 oxalic acid has a volume 9*8 x 4 ; oxalate of potash possesses the 

 volume 11x3, and passes with this volume into the binoxalate 

 and quadroxalate of potash, the oxalic acid in the binoxalate 

 being associated as two volumes of ice, although the water of 

 crystallization possesses the volume 11. Quadroxalate of 

 potash is to be viewed as anhydrous binoxalate plus 2 equiv. 

 hydrated oxalic acid, the latter having become 11x4 instead 

 of 9*8 X 4. The same explanation applies to the binoxalate 

 and quadroxalate of ammonia, the only difference being that 

 anhydrous oxalate of ammonia, 9" 8 x 4, takes the place of 

 oxalate of potash. On these views the following table is con- 

 structed. - -, . ■ ' ' 



JesU) ^rigBJoq io 9Jfi]iixoibi!i»p fli i'l iH'n' noltulog otci p/e^iiiki^?, 

 Table Xn.--^howiiig^ithe volumes bcfeupiecl by Hjertaan DxsJates. 



r'P^tS^'^m'.", .. ill 



deijitoi 



Vol. in solution. 



Volume in state of salt. 



Name. 



'd-t 



CM 



♦jaoxji 9Yod« noiiti/Ioa ni >, 

 ftid "^o oii^i'iiKi'iUtBiI.) 



i fUBXC 



'\ \,\uf 



Oxalic acid 



Oxalate of potash... 

 Oxalate of ammo- 1 



nia J 



Binoxalate of pot- \ 



ash J 



Binoxalate of am- 1 



monia..... J 



Oxalate of copper 1 



and potash J 



Oxalate of copper \ 



and ammonia... j 

 Quadroxalate of 1 



potash J 



Quadroxalate ofl 



ammonia J 



ZF 



I] u 



TTWrf 



44- 



*0,C2 03-F2HO 

 KCCzOg+HO 



11 









en .a 



NH40,C2 03-|-HO 

 KO,2C2 03-}-3HO 



NH40,2Ca03-f-3HO 



KO.CjOa-HCuO.CaO. " 



+ 2H0 

 NH4O, C2 Og+CuO.Ca O3 ' 

 -f-2H0 ' 



KO4C2O3 + 7HO 

 NH40,4C2 03-|-7HO , 



63-26 

 92-39 



71;43 

 146-63 

 125-67 

 177-25 

 156-k 

 25511 

 234-15 



36-6 



28-2 



36-0 

 53-6 

 71-9 

 54^ 

 7^-3 

 1171 

 134-5 



36 

 27 



36 

 54 

 72 



-5i4 

 >2 

 117 

 135 



39-0 

 43-9 



48-9 

 74-6 

 8P-4 





140-4 

 147-4 



13 



«' i 



14 



39-2 

 44-0 



49-0 

 74-6 

 80-8 



'm 



140-6 

 146-8 



1-616 1-622 

 2-1002104 



1-4581-461 

 1-9651-965 

 1-5551-563 

 2-301,2-288 

 1-9351-923 

 1-814 1-817 

 1-5951-589 



The examination of the volumes occupied by the oxalates 

 presents several points of great interest. The volume of oxalic 

 acid itself is a multiple of the volume of ice, or 9*8 x 4. 



Oxalate of potash in its solid state possesses four volumes, 

 11 X 4, but loses one volume on passing into solution, as 

 usually is the case with neutral salts of potash. As one of 



