London Electrical Society. 61 



employed for Bessel's zones, the values of the constants, /, g, h, i, 

 G, H, of the Berlin Ephemeris being adopted ; and in the annual 

 variations no allowance has been made for proper motions of any of 

 the stars. 



LONDON ELECTRICAL SOCIETY. 



Feb. 15, 1842. The papers read were, — 1st, "On the Electrical 

 relation between Plants and Vapours." By Mr. Pine. The author, still 

 pursuing the same path as that traced out in his former communica- 

 tions, makes copious extracts, from various quarters, both of natural 

 and experimental facts, in support of his views of the relation be- 

 tween the subtle fluid— electricity, and the functions of vegetable 

 life. His opmions and reasonings are worthy of examination. 



2nd, " Further Observations on Electrotype Manipulation — Depo- 

 siting on Plumbago — Electro-lace." By Charles V. Walker, Esq., 

 Hon. Sec. The difficulty attendant on the reduction of copper upon 

 the parts of plumbagoed surfaces most remote from the connect- 

 ing wire, is obviated by a very simple process. One or more fine 

 leading wires are twisted round the main wire, and made to abut 

 upon any part of the surface where the reduction has not occurred. 

 The value of this apparently trivial piece of information can be ap- 

 preciated by experimentalists alone. The material, to which the 

 term " electro-lace" has been given (and of which specimens were 

 before the Society), is obtained by depositing copper upon net or 

 lace, previously prepared with wax and black-lead. It was first fa- 

 bricated by Mr. Phillips of Cornwall, in lieu of the copper gauze re- 

 quired in the construction of Prof. Grove's modification of Smee's 

 battery. But it will be readily seen that such fabrics as gauze and 

 lace, when covered with copper, and plated or gilded, may be intro- 

 duced, in a multitude of ways, into the construction of ornamental 

 work, where at present embossed and perforated cards are employed. 

 3rd. " Nitrate of Soda compared with other Salts employed for 

 Constant Batteries." By Geo. Mackrell, Esq., Mem. Elec. Soc. Cells 

 were excited with solutions of sulphate of copper, bichromate of 

 potash, nitrate of potash, and nitrate of soda. The palm of supe- 

 riority, for constancy of action, is awarded to the latter : in addition 

 to this, when employed for electrotype purposes, it throws down 

 more copper in proportion to the zinc consumed, than either of the 

 other three : the zinc plates (no slight advantage) are clean when 

 removed from the battery. 



Mr. Weekes's Register for January was next read. At the sug- 

 gestion of several scientific correspondents, with a view to promote 

 the objects of coincident observation, Mr. Weekes begins the Register 

 of 1842 by giving the readings of the barometer and thermometer at 

 9 a.m. instead of 2 p.m. 



March 15. — The papers read were, — 1st, "Details of an experi- 

 ment, in which certain insects, known as the Acarus Crossii, appeared, 

 incident to the long-continued operation of a voltaic current upon 

 Silicate of Potash within a close atmosphere over mercury." By 

 W. H. Weekes, Esq. 



