1902.] Cubical Expansion of Ice, etc., at Low Temperatures. 237 



Lastly, in the rhipidoglossate Gastropods, there is a caecum but appa 

 rently no sac. 



In conclusion, it would therefore appear that the so-called gizzard 

 of Spirula and Nautilus, and consequently the similar organ which 

 appears in other Cephalopods, is in reality the homologue of the 

 style-sac of the Gastropods and the Lamellibranchiata. That in the 

 Cephalopods only that portion of the gastric tube which lies between 

 the orifice of the oesophagus and the intestine is the true stomach and 

 consequently comparable to the true stomach of the Gastropods, while, 

 lastly, the valvular diverticulum in relation to the " bile duct " in the 

 Cephalopods is unquestionably the homologue of the similarly related 

 and so-called spiral caecum which projects from the true stomach of the 

 Gastropods. 



"Coefficients of the Cubical Expansion of Ice, Hydrated Salts, 

 Solid Carbonic -Acid, and other Substances at Low Tempera- 

 tures." By James Dewak, M.A., D.Sc, LL.D., Jacksonian 

 Professor, Cambridge University, and Fullerian Professor, 

 Eoyal Institution, London. Keceived April 16, — Eead 

 May 1, 1902. 



The apparent specific gravities of boiling liquid oxygen which 

 resulted from weighing in the liquid a series of metals and other 

 substances were given in a lecture entitled " New Eesearches on Liquid 

 Air," printed in the Eoyal Institution ' Proceedings ' for 1896. For 

 instance, silver, calc spar, rock crystal, and iodide of silver gave the 

 respective apparent densities 1*1278, 1*1352, 1*1316, and 1*1372. On 

 correcting the weight of liquid displaced by each substance for con- 

 traction to - 182°*6 — by calculating a Fizeau mean coefficient of 

 expansion for the range of temperature employed, on the assumption 

 that the parabolic formula might be legitimately extended to low 

 temperatures, — it was found that the real density of liquid oxygen so 

 deduced for all the bodies used was, as a mean, 1*137. 



The determination of the densities of substances at the temperature 

 of the boiling-point of oxygen, — and hence of their mean coefficients 

 of expansion between that temperature and ordinary temperatures, — 

 opens out a very large field of investigation, from which, if a suffi- 

 ciently large number of observations were available, valuable deduc- 

 tions might be drawn. On account, however, of the expense and 

 trouble of producing quantities of liquid oxygen, its use for this 

 purpose is not likely to become general, although, when available, it is 

 the easiest body to use in conducting such experiments, especially when 

 the vacuum vessel containing it is immersed in a larger vessel contain- 

 ing the same fluid or well evaporated air. The ease with which liquid 



