Prof. E. Wartmann's Seventh Memoir on Induction. 439 



pendent imaginaries i,J t k, we should have to deal, not with 

 tessarines, but with what might be called octrines. These last- 

 mentioned expressions would be of the form 



w + i x +jy + kz + ijp + ikq +jkr + ijks, 



where w, x, y, z, p, q, r, s are any real quantities. These 

 quantities might be termed the constituents of the octrine, 

 which could not vanish unless all its constituents were zero. 

 So if we had four independent imaginaries (that is to say, 

 imaginaries unconnected by any linear relation), the corre- 

 sponding expression would consist of sixteen terms, and would 

 have properties analogous to those of the tessarine and the 

 octrine. I must here break off, but I remain, always, 



My dear Sir, 



Yours most truly, 



James Cockle. 

 To T. S. Davies, Esq., F.E.S. L. $ E. 9 

 fyc. Sj-c. fyc.y Woolwich. 



LXV. Seventh Memoir on Induction. ByM. Elie Wartmann, 

 Professor of Natural Philosophy in the Academy of Geneva*. 



[Continued from p. 278.] 



§ XIX. On the relations of Electricity with bodies in the sphe- 

 roidal state, and on some properties of those bodies. 



178. TT is a well-known fact that liquids are incapable of 

 A moistening solid surfaces sufficiently heated, or of 

 mixing, in certain cases, with other liquids raised to a high 

 temperature. The first accurate observation of this fact is 

 attributed to Eller: it dates from 1746"f\ Ten years later, 

 this phaenomenon was studied by Leidenfrost, by whose name 

 it is still designated {. Since then a number of experiments 

 little known have been made in Germany § ; afterwards Italy || 



* Communicated by the Author. 



if Histoire de P 'Academic de Berlin, 1746, p. 42. 



\ De aquce communis nonnullis qualitatibus : Duisburg, 1756. 



§ Among others we may cite Ziegler, Specimen de digestore Papini,\765. 

 — Link, Beitrcige zur Physik und Chemie, No. 2, p. 11. — Kastner, Troms- 

 dorff 's Journal, vol. ix. p. 270. — (Ersted, Gehlen's N. Allgem. Journ.,\o\. iii. 

 p. 324. — Klaproth, Scherer's Allg. Journal de Chemie, vol. vii. p. 646 ; and 

 Journal de Physique, 1802, p. 62. — Dobereiner, Schweig. Journ., vol. xxix. 

 p. 43. — N. W. Fischer, Poggend. Annalen, vol. xix. p. 514, and vol. xxi. 

 p. 163. — Buff, Pogg. Ann., vol. xxv. p. 591. — A. H. Emsmann, Pogg. Ann., 

 vol. li. p. 444. — Frei, Kastner's Archiv, vol. iv. p. 57- — Erdmann, Journal 

 fiir Praklische Chemie, vol. x. p. 334. — Bollger, Eine Sammlung eigener Er- 

 fahrungen, Versuche und Beobachtungen,No. 18, Francfort-sur-Mein, 1838. 



|| Bellani, Giornale di Fisica di Brugnatelli, 1808, p. 779; Giornale di 



