Proceedings of Learned Societies. 145 



decomposition of a small portion of water which has adhered to the 

 chloride of ammonium (sal ammoniac) and chloride of zinc, employed 

 to cover the bath of melted zinc used to " galvanize " the iron. An 

 electrolytic action subsequently takes place, during which the film 

 of water is decomposed, the oxygen uniting with the zinc, and the 

 hydrogen being liberated in the gaseous form. In tracing its pro- 

 bable origin, Mr. Abel discovered that chloride of zinc, when once 

 combined with water, could not be again rendered perfectly anhydrous 

 by exposure to a degree of heat somewhat above the melting point 

 of zinc ; for on throwing fragments of zinc into the fused chloride 

 they were quickly melted, giving rise to the production of hydrogen 

 gas, and the formation of an oxychloride of the metal. It was not 

 difficult to suppose a similar change occurring in the lapse of time 

 at the ordinary temperature ; chloride of zinc would undoubtedly be 

 formed by the action of the sal-ammoniac flux upon zinc or its oxide, 

 and this might readily attach itself to slight asperities upon the sur- 

 face of the shot, become hydrated, and ultimately enclosed within 

 the lead coating. The torn, fibrous aspect of the metal on the inner 

 surfaces of the blister, and the detection of chlorine in the cavities, 

 confirmed these opinions, and pointed directly to the origin of these 

 remarkable appearances upon the Armstrong shot. 



ENTOMOLOGICAL SOCIETY.— July 6th. 



Hermaphrodite Form op Papilio. — Professor Westwood ex- 

 hibited specimens of two species of butterfly, Papilio Castor and 

 Papilio Pollux, which by some naturalists have been regarded as 

 the two sexes of one and the same species. Professor Westwood, 

 however, possessed males of both forms, and the female of P. Pollux. 

 One specimen of Papilio Castor was remarkable as showing the 

 forms of both sexes, or rather as having a gynandromorphous wing, 

 part of which, both on the upper and under sides, exhibited the 

 colorations and marking of the male, and part on both sides having 

 the colours and markings of the female. It was remarkable, how- 

 ever, that neither the male nor the female markings correspond on 

 both sides of the wing. From these peculiar circumstances, Profes- 

 sor Westwood maintained that the Papilio Castor and Papilio Pollux 

 were not the two sexes of one species, but in reality two perfectly 

 distinct species. 



GEOLOGICAL SOCIETY. 



On the Occurrence of Albertite at Mountgerald, Scotland. 

 By A. C. Mackenzie, Esq. Communicated by Professor J. Tennant, 

 F.G.S. — In making a drain on a farm near Mountgerald, a fissure 

 was discovered which contained a bituminous substance very similar 

 to the Albertite of New Brunswick ; a deposit of a similar nature 

 was also discovered in making a cutting through " The Craig," 

 near Mountgerald. The author described the stratigraphical and 

 lithological characters of the rocks met with in making this cutting, 

 and stated that as many as thirty-six veins containing this mineral 



