54 Royal Society. 



brown colour, were observed attached to the membrane, and con- 

 nected with each other by a beautiful network of moniliform fibres. 

 Numerous siliceous spicula, pointed at both extremities and exceed- 

 ingly minute, were discovered in the membranous structure of se- 

 veral corals ; and also other spicula of larger size, terminated at 

 one extremity in a point, and at the other in a spherical, head ; a 

 form bearing a striking resemblance to that of a common brass pin. 



Besides these spicula, the author noticed in these membranous tis- 

 sues a vast number of minute bodies, which he regards as identical 

 with the nuclei of Mr. Robert Brown, or the cytoblasts of Schleiden. 



A paper was also in part read, entitled, " Sixth Letter on Voltaic 

 Combinations," addressed to Michael Faraday, Esq., D.C.L., F.R.S., 

 &c. By John F. Daniell, Esq., For. Sec. R.S., Professor of Che- 

 mistry in King's College, London, &c. 



May 5. — The reading of a paper, entitled, ""Sixth Letter on Voltaic 

 Combinations," addressed to Michael Faraday, Esq., D.C.L., F.R.S., 

 Fullerian Professor of Chemistry in the Royal Institution of Great 

 Britain, &c, by John Frederic Daniell, Esq., Foreign Sec. R.S., 

 Professor of Chemistry in King's College, London, was resumed 

 and concluded. 



The purport of this letter is to follow the consequences of the law 

 of Ohm, and the expressions which result from it, relative to the 

 electromotive force, and to the resistances in the course of a voltaic 

 circuit ; to apply this theory to the verification of the conclusions 

 which the author had formerly deduced from his experiments ; and 

 to suggest additional experiments tending to remove some obscu- 

 rities and ambiguities which existed in his former communications. 

 In following out these principles,- the author is led to offer various 

 practical remarks on the different forms of voltaic batteries which 

 have been proposed with a view either to the advancement of our theo- 

 retical knowledge of the science, or to the service of the arts. The 

 author enters more particularly into an explanation of the principles 

 on which the cylindric arrangement of the battery he has intro- 

 duced is founded, which appear to him to have been greatly misun- 

 derstood. The formulae and the calculations which form the body 

 of this paper are not of a nature to admit of being reported in the 

 present abstract*. 



May 12. — " On the Rectification and Quadrature of the Spheri- 

 cal Ellipse." By James Booth, Esq., M.A., Principal of Bristol Col- 

 lege. Communicated by John T. Graves, of the Inner Temple, Esq., 

 M.A., F.R.S. 



The author, at the commencement of this paper, adverts to a 

 rather complex discussion of a portion of the subject of his inquiry 

 by M. Catalan, published in the Journal de Mathematiques, edited 

 by M. Liouville. 



He then proceeds to establish two fundamental theorems, appli- 



[* Abstracts of Prof. Daniell's preceding five letters on Voltaic Combi- 

 nations have already been given in Phil. Mag., Third Series; see vol. xv. 

 p. 312. Dr. Martin Barry's paper on Fibre, also read May 5, will be no- 

 ticed in a future Number, together with Lieut.-Col. Yorke's on the Effect 

 of the Wind on Barometers, read May 12th.— Edit.] 



