TRANSACTIONS OF SECTION B. 



677 



Hie fonndation of his systom has heen amply shown not to exist ; by Staedel for 

 clilorino, and by Kopp and others for nitrogen, oxygen, and sulphur. 



5, On comparing the molecular volumes of compounds containing carbon, 

 l.ydrogen, and oxygen, with the number of atoms contained in the compound, it is 

 ((i)servable that in ever}' case approximate proportionality is to be observed. Thia 

 v:ould imply that these elements enter the liquid state with approximately the 

 s;inui volumes which they would possess before combination, were it possible for 

 iJit'SB to exist in a perfect gaseous state. Expressed differently, tiie quotient 

 (ihtiiiued by dividing the molecular volume of a compound by the number of atoms 

 (•■iiitiiiui'd in the compound yields a nearly constant number. This has been 

 luticed by Schroder. Ihit in order to reconcile the discrepancy observable 

 botwoen (iiflerent series, Schroder bus supposed that the atoms of some elements 

 possess at one time doul)le or treble the volume which they exhibit at another 

 t.-rae. The autluu" has shown that Scliriider's method does not reconcile the 

 observed discrejiancies. On attempting to correlate the divergency from the 

 nlmve-mentioned very simple relation with the heats of formation of organic 

 s-.ibstanc<}S, no absolute regularity is noticeable, alth(jugh there is general corre- 

 spondence between a large molecular volume and a small evolution of heat during 

 formation of the compound from its elements. 



10. On Calcium Sulphide and Snlphocarhonate. 

 By V. H. Veley, M.A., F.C.S. 



Bevzeliup. ' Schweigger Journ.,' 34.1 2, has described a process for the preparation 

 ■rif calcium sulphide b}' passing hydrogen sulphide over lime, heated to a red heat. 

 Tlio equivalent weights of the water and calcium sulphide as the resultants of the 

 ■KiUiition, 



('aO + H,S:CaS-'.-n,0 



v;ere found to be in the proportion of 87 : 89 or practically 1:1. 



In another memoir, Herzelius, ' I'ogg. Annal.,' (!.444, describes the preparation of 

 cnlcium sulphocarbonate by digesting calcium sulphide, water, and carbon disulphide, 

 at a temperature of 00' in a ilask from which air is excluded. 



C'nhium Sulphide.^S.^ the formation of calcium sulphide is involved in the 

 ];rocesses of purification of coal gas, and presumably abstracts the carbon disulphide 

 l'"'.iiu gas contaminated with that substance, it seemed of interest to study more 

 particularly the formation of these compounds by the methods indicated by 

 llt'i'Zt'liiis. 



Calcium oxide, free from the metals of the iron group, was obtained by heating 

 ])erfectly transpai'ent crystals of Icelantl spar in porcelain tube in a current of 

 iiydrogen. This oxide was hydrated in a damp atmosphere free from carbonic 

 tuihydride, and converted into the hydroxide Ca (OII)o. 



The hydroxide, introduced into a convenient apparatus, was heated to 00", and 

 hydrogen sulphide passed through it, air being carefully excluded throughout the 

 experiment. The resultant calcium sulphide and water were weighed, and the 

 synthetic results thus obtained were found to agree with the results of the analysis 

 of the calcium sulphide. 



It is worthy of note that perfectly dry calcium oxide is ])erfectly unaltered by 

 the passage of perfectly dry hydrogen sulphide, and generally the formation of 

 talcium sulphide proceeded th^ more rapidly the greater the quantity of water 

 originally present in the hydroxide. This result may be due to the formation at 

 first, either of the hydrcsulphide CaSII, SIl, or hydroxyhydrosulphide Ca, OH, 

 SII, and the conversion of either of these substances into the monosulphide. 



Calcium Snipliorarbonate. — The calcium sulphide, prepared as described above, 

 was moistened with water, and hydrogen, saturated with carbon disulphide, was 

 passed through it. It gradually turned yellow, and finally red, and on exhaustion 

 with cold water there was obtained a red solution, from which on evaporation in 

 vacuo there separated red deliquescent, prismatic crystals. The composition of 

 these crystals on analysis was found to be in accordance with the formula Ca(OH)a. 



M, 



' > 



