52 



ingly conducted in preference to other lines of transit. The variety 

 in the appearance of the electric spark taken in dilFerent gases may 

 be ascribed partly to different degrees of heat evolved, but chiefly to 

 specific properties of the gas itself with relation to the electric forces. 

 These properties appear also to give occasion to diversities in the 

 form of the pencil or brush, which takes place when the discharge 

 is incomplete, and is repeated at short intervals, according to the 

 shape of the conductor on either side, and according to the species 

 of electricity conveyed. The diverging, converging, bent and rami- 

 fied lines presented in these different forms of electric discharge, 

 strikingly illustrate the deflexions and curvilinear courses taken by 

 the inductive actions which precede the disruption ; these lines being 

 not unlike the magnetic curves in which iron filings arrange them- 

 selves when under the action of opposite magnetic polarities. 



March 8, 1838. 



FRANCIS BAILY, Esq., V.P. and Treas., in the Chair. 



Colonel Andrew Leith Hay, K.H., who had at the last Anniver- 

 sary ceased to be a Fellow from the non-payment of his annual con- 

 tribution, was at this meeting re-elected by ballot into the Society. 



A paper was read, entitled, " Proposal for a new method of de- 

 termining the Longitude, by an absolute Altitude of the Moon," by 

 John Christian Bo wring, Esq. Communicated by John George 

 Children, Esq., F.R.S. 



The method employed by the author for determining the longitude 

 by the observation of an absolute altitude of the moon, was pro- 

 posed, many years ago by Pingre and Lemmonier; and the princi- 

 pal difliculty which stood in the way of its adoption, was its re- 

 quiring the exact determination of the moon's declination reduced 

 to the place of observation. This difficulty the author professes to 

 have removed by supposing two meridians for which the altitudes 

 are to be calculated : and the only remaining requisite is the accu- 

 rate determination of the latitude, which presents no great difficulty, 

 either on land or at sea. Examples are given of the practical work- 

 ing of this method ; showing that if the latitude of a place of obser- 

 vation be obtained within a few seconds, the longitude will be found 

 by means of a single observation of the altitude of the moon. 



A paper was also read, entitled, " An Inquiry into a new Theory 

 of earthy Bases of Vegetable Tissues," by the Rev. J. B. Reade, 

 M.A., F.R.S. 



The author, after briefly noticing the results of some of his expe- 

 riments described in two papers which appeared in the Philosophical 

 Magazine for July and November, 1837, and also those of Mr. Ro- 

 bert Rigg in a paper read to the Royal Society, next adverts to the 

 theory of M. Raspail, detailed in his T ahleau Synoptique, and Nou- 

 veau Systeme de Chimie. In opposition to some of the views enter- 



