Transactions of the Royal Society. 355 



every other substance in this quality. It has already been ap- 

 plied to this purpose. 



It will answer all the purposes to which the essential oils 

 are applied as solvents, as in Varnishes, <§rc, and in some cases 

 where volatility is required, when rectified it will far surpass 

 them. 



It is possible that, at some future time, when we better under- 

 stand the minute changes which take place during the decompo- 

 sition of oil, fat, and other substances by heat, and have more 

 command of the process, that this substance, among others, may 

 furnish the fuel for a lamp, which remaining a fluid at the 

 pressure of two or three atmospheres, but becoming a vapour at 

 less pressure, shall possess all the advantages of a gas lamp, 

 without involving the necessity of high pressure. 



xii. Account of the repetition of M. Arago's experiments on the 

 Magnetism manifested by various substances during the act of 

 rotation. By C. Babbage, Esq. F.R.S., and J. F. W. Herschel, 

 Esq. Sec. R.S. 



Though this paper is merely stated to refer to a repetition of 

 M. Arago's experiments, it may in fact be considered as a distinct 

 and somewhat elaborate investigation founded upon a report of 

 the very singular results obtained by that celebrated physical 

 inquirer. Having already laid before our readers an outline of 

 its contents, and intending, upon an early occasion, to give a con- 

 nected view of the very singular discoveries in magnetism which 

 every day is bringing forth, we shall at present merely recommend 

 those who are experimentally engaged on the subject, to study 

 Messrs. Babbage and Herschel's paper. 



xiii. On the Magnetism developed in Copper and other Substances 

 during rotation. In a Letter from Samuel Hunter Christie, 

 Esq., M.A., #c, to J. F. W. Herschel, Esq., See. R. S. Com- 

 municated by J. F. W. Herschel, Esq. 



xiv. On the Annual Variations of some of the principal fixed Stars. 

 By J. Pond, F.R.S. Astron. Royal. 



xv. On tlve Nature of the Function expressive of the Law of Human 

 Mortality, and on a new Mode of determining the Value of Life 

 Contingencies. In a Letter to Francis Baily, Esq., F.R.S. fyc. 

 By Benjamin Gompertz, Esq., F.R.S. 



In respect to these which are the concluding papers of the 



