679 JRoynl Imliluiion. 



and, having taken a general view of tlie pli<cnomena of crystalli- 

 zation, noticed at considerable length the theories which had 

 been invented to account for them. 



It will be impossible to give an intelligible outline of that part 

 of Mr. Brande's lecture in which he exposed the theories of 

 cr>'stallization : those of Rome de Lisle, of Haiiy, and of Dr. 

 Wollaston, were separately considered, and illustrated by a series 

 of excellent models. The Professor supported that hypothesis 

 which regards the primitive forms of crystals, as. made up of sim- 

 ple arrangements of spherical particles ; and some new facts upon 

 the subject were adduced, which, if not perfectly demonstrative, 

 were highly favourable to thiese views. 



In his twelfth lecture Mr, Braude entered upon the subject 

 of electricity, with an historical sketch of the rise aad progress 

 of that branch of experimental science. Theophrastus, the ce- 

 lebrated pupil and successor of Aristotle, is the first who alludes 

 to this singular power of matter. Dr. Jelbert is the earliest 

 scientific writer on this subject, and in his treatise on magnetism, 

 published in 1600, many important facts concerning the excita- 

 tion of electricity are detailed. Having detailed tliesc and other 

 di'ieoveries in chronological order, the Professor proceeded to a 

 r.cnes of cqierimcnts illustrating the laws of electrical excitation, 

 The phenomena of viduccd elediicity, and the other modes of 

 excitation, were also considered. 



Mr. Brande said that it was only within the last fourteen years 

 that the chemist had been required to enter minutely upon this 

 .vabject of inquiry ; for, although it might have been suspected 

 that an agent po powerful and so universal as electricity was not 

 unconnected with the chemical energies of malter, no suoh rcr 

 lationship had been demonstrated until the commencement of 

 the present century, an aera which, would ever be referred to, as 

 among the most glorious and important in experimental science. 



Mr. Brande described the different elect) ometers, or instru- 

 ments for ascertaining the presence and measuring the quantity 

 of electrical excitation, and concluded with details rcspectii^ig 

 the discoveries of Dr. Franklin, especially as to the modes of 

 preserving ships and })uildings from the effects of lightning, and 

 with some observations on his scientific character. 



Mr. Brande in his thirteenth lectme resumed the subject of 

 electricity. He dwelt upon the different modes of excitation 

 {■hortly noticed in his former discourse, and referred the phaeno- 

 mcna of the thunder-storm and water-spout, to induction taking 

 place between the clouds and the earth and water. He illustrated 

 the meaning of tiie terms qitantify and infevsifi/, as employed 

 by electricians ; the former signifying the absohite quantity of 

 electricity diffused over any surface ; the latter, its tendency to 



