Wellington Philosophical Society. 697 



vating the natural enemies of pests ; and, also, as he taught California 

 how to clear away Icerya, he taught New Zealand too tlie way to extir- 

 pate it. 



]Mr. IMaskell desired to cordially indorse all that the Chairman had 

 said, and ventured to add a word or two as to Mr. Koobele's present 

 work. That gentleman had recognised the benefit which New Zealand had 

 done to California in giving it Vcdalia, and now Mr. Koebele was trying to 

 repay the benefit by introducing to this country and liberating in Auck- 

 land insect-parasites from America which would, he hoped, prey largely 

 upon the other " blights " existing here. If America owed something to 

 New Zealand, it was now the turn of New Zealand to thank an American 

 for trying his best to give us a practical benefit in return. He would 

 venture also to say that in America, had there not existed expert Agricul- 

 tural Departments and expert Boards, Mr. Koebele's two visits would 

 probably have never taken place, and they furnished, therefore, an 

 additional very strong argument in favour of the resolution passed lately 

 both by this Society and by the Legislative Council, to the effect that 

 an expert Agricultural Department should be established here, instead of 

 the sham now existing. 



Paper. — " On Stereo-chemistry, or the Arrangement of 

 Atoms ; being the Latest Phase in the Development of the 

 Atomic Theory," by W. P. Evans, M.A., Ph.D. 



Abstract. 



The author sketched briefly the older radical and type theories, 

 showing how each failed to lay sufficiently bare the internal structure of 

 the molecule. The chain theory was then gone into at some length, and 

 its inability to explain many well-known cases of isomerism pointed out. 

 Having thus made evident the necessity for widening the theory, the 

 author proceeded to explain the stereo-chemic hypothesis of Lo Bel and 

 van't Hoff. By help of models, the possible derivatives of a single 

 carbon and the combinations of two such systems were developed, it being 

 thus shown how two hitherto unknown classes of isomers were rendered 

 possible — viz., those due to the presence of asymmetric carbon-atoms, 

 and those due to the presence of doubly-bonded pairs of carbon-atoms. 

 Many examples from organic chemistry were then given in support of the 

 hypothesis, special stress being naturally laid on those compounds {e.g., 

 tartaric acid, amygdalic acid, malic acid, propylene glj^col, amylic 

 alcohol, camphor, &c.) whose optical activity was not dependent on the 

 solid state. In conclusion, attention was drawn to the fact that the 

 stereo-chemic method had already been extended to other elements, 

 notably nitrogen and oxygen; that it had done much service in the 

 development of organic rings, had exx^lained in a very satisfactory manner 

 several hitherto abnormal anhydrides and oximes, and bade fair to be oi 

 considerable use in comparing the chemical energies of the several 

 members of any special group. 



Sir James Hector complimented the author on his splendid paper. 

 He hoped that before long tlie services of Dr. Evans would be secured as 

 a teacher in one of our colleges. He pointed out how necessary it was 

 for Wellington to have a college where a lecture of this kind would be of 

 much benefit to students, and he hoped Dr. Evans would on a future 

 occasion give the Society further experimental proofs of the theories he 

 advanced. 



Mr. Hulke said he had listened with great pleasure, for the subject 

 of the paper bad been for some time past of great interest to him. 

 If there was any foundation of truth in the theory, then the polariscope 

 would be to the chemist what the spectroscope was to the astronomer. 

 All innovations met with opposition. When, half a century ago, the in- 



