350 



system, so also will a similar direction be given to the effects of ex- 

 ternal motion. Every motion tending to propel forward the blood, 

 will hence assist the powers of the heart ; but such as have a con- 

 trary tendency will be resisted by the interposition of the valves, and 

 cannot occasion proportional obstruction to the regular progress of 

 the blood ; the heart is thus assisted in the work of restoring a sy- 

 stem, which has recently struggled with some violent attack, or al- 

 lowed, as it were, to rest from a labour to which it is no longer equal, 

 when the powers of life are nearly exhausted by some lingering dis- 

 order. 



It is conceived that all the other animal functions must participate 

 in the relief thus afforded to so important an organ ; and it is re- 

 marked, that even the powers of the mind itself, though most remote 

 from our conception of material agents, are, in many persons, thus 

 immediately affected, by the consequences of a merely mechanical 

 operation. 



The Bakerian Lecture for 1809. On some new Electrochemical Re- 

 searches, on various Objects, particularly the metallic Bodies, from 

 the Alkalies, and Earths, and on some Combinations of Hydrogen. 

 By Humphry Davy, Esq., Sec. R.S. F.R.S.E. M.R.I.A. Read 

 November 16, 1809. [Phil. Trans. 1810,^. 16.] 



Mr. Davy having from the commencement of his electro-chemical 

 researches, communicated the several steps of his progress to the 

 Society, takes the present opportunity of reporting the results of his 

 further inquiries under four principal heads. First, on the nature of 

 the metals of the fixed alkalies. Second, on the nature of hydrogen 

 and composition of ammonia. Thirdly, on the metals of the earths ; 

 and, Fourthly, he makes a comparison between the antiphlogistic 

 doctrine, and a modified phlogistic hypothesis. 



When Mr. Davy first communicated to us his discoveries of potas- 

 sium and sodium, he adopted, as most probable, the antiphlogistic 

 interpretation of the phenomena, and considered potassium and so- 

 dium as simple metallic bodies, of which potash and soda are the 

 oxides. The same experiments have since been repeated by others 

 with the same results, but the explanations given by different che- 

 mists have been various. The theory which has appeared most de- 

 serving the author's notice, and is more particularly controverted, is 

 that of Messrs. Gay-Lussac and Thenard, w r ho conceive these metals 

 to be compounds of their respective alkalies with hydrogen; although 

 in the interpretation of their own production of a metallic substance 

 from boracic acid, they relapse again into the antiphlogistic doctrine, 

 and suppose themselves to have effected a decomposition, by abstrac- 

 tion of oxygen from it. 



Since the principal experiment on which Messrs. Gay-Lussac and 

 Thenard rely, is that in which ammonia is acted upon by potash, Mr. 

 Davy details a great number of modes in which he has varied the 

 experiment with the utmost care to avoid moisture, which appears to 



