TKASS ACTION'S OF SECTION B. 677 



the 'foundation of his system has been amply shown not to exist ; by Staedel for 

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



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

 hydrogen, and oxygen, with the number of atoms contained in the compound, it is 

 observable that in every case approximate proportionality is to be observed. This 

 would imply that these elements enter the liquid state with approximately the 

 same volumes which they would possess before combination, were it possible for 

 these to exist in a perfect gaseous state. Expressed differently, the quotient 

 •obtained by dividing the molecular volume of a compound by the number of atoms 

 ■contained in the compound yields a nearly constant number. This has been 

 noticed by Schroder. But in order to reconcile the discrepancy observable 

 between different series, Schroder has supposed that the atoms of some elements 

 possess at one time double or treble the volume which they exhibit at another 

 time. The author has shown that Schroder's method does not reconcile the 

 observed discrepancies. On attempting to correlate the divergency from the 

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

 substances, no absolute regularity is noticeable, although 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 Sulplwcarbonate. 

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



Berzelius, ' Schweigger Journ.,' 34.12, has described a process for the preparation 

 <5f calcium sulphide by passing hydrogen sulphide over lime, heated to a red heat. 

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

 equation, 



CaO + H,S:CaS-!-H 2 



were found to be in the proportion of 87 : 89 or practically 1:1. 



In another memoir, Berzelius, ' Pogg. Annal.,' 0.414, describes the preparation of 

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

 at a temperature of 30° in a flask from which air is excluded. 



Calcium Sulphide. — As the formation of calcium sulphide is" involved in the 

 processes of purification of coal gas, and presumably abstracts the carbon disulphide 

 tiom gas contaminated with that substance, it seemed of interest to study more 

 particularly the formation of these compounds by the methods indicated by 

 Berzelius. 



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

 perfectly transparent crystals of Iceland spar in porcelain tube in a current of 

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

 anhydride, and converted into the hydroxide Ca (OII) 2 . 



The hydroxide, introduced into a convenient apparatus, was heated to 60°, 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 worth}' of note that perfectly dry calcium oxide is perfectly unaltered by 

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

 culcium sulphide proceeded tli3 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 hydrosulphide Ca SH, SH, or hydroxyhydrosulphide Ca, OH, 

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



Calcium Sulphocarbonate. — 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) 3 . 



