580 Transactions. — Phi/sics. 



The data for the even membeis of the normal fatty esters 

 are given in Table II. D represents the initial molecular 

 depression for a fall of 05°. 



Table II. 



N. Ester. D. 



2 Ethyl acetate 75 



4 Ethyl butyrate 79 



6 Ethvl hexoate 98 



8 Ethyl octoate 



10 Ethyl decoate 81 



12 Ethyl laurate 79 



14 Ethyl myristate 81 



16 Ethyl palmitate 88 



18 Ethyl stearate 82 



The values of D are plotted against N (the number of 

 atoms in the acid portion of the molecule) in fig. 2. The 

 resulting curve shows a minimum and two distinct maxima. 



According to Baeyer's tension theory a chain of six carbon 

 atoms bends l'ound to form a ring in space. But, as shown 

 above, there is a considerable tendency for the formation of 

 maxima or minima in the case of compounds with a chain of 

 six and twelve carbon atoms. Hence it appears that asso- 

 ciation, which has been shown to cause the appearance of 

 a maximum or minimum, is largely influenced by the arrange- 

 ment of the atoms in space. Further, the regular rise and 

 fall in the properties of the esters of the fatty acids can be 

 explained on the assumption of Baeyer's hypothesis of the 

 configuration of a chain of carbon atoms in space. 



Art. LXII. — A Flash of Lightning. 

 By Archdeacon Walsh. 

 [Read before the Auckland Institute, 12th September, 1904.] 

 About last February a thunderstorm passed over the district 

 of Taiamai, a tract of volcanic country lying about half-way 

 between the Bay of Islands and Hokianga. The discharges 

 were not very frequent, but were unusually heavy. One of 

 them fell in a fairly level paddock close to the coach-road from 

 Ohaeawai to Kaikohe, about half a mile from the former place. 

 A wagon drawn by a team of horses was passing at the time, 

 when the horses, terrified by the blinding flash, bolted, and 

 the wagon was upset. It was raining in torrents, and a 

 couple of Maoris, who were standing under the verandah of a 

 cottage some three or four hundred yards off, stated that the 



