The Three Secretaries 147 



"Times — mornino-, noon, and night, or morning and night. 

 Most important observations : i. Barometer. 2. Face of the 

 sky. 3, Direction and force of the wind. The rise of the 

 barometer will precede a fall." 



Under May 19, is the following entry : 



"Wrote to Judge McLean to give me an account of his 

 obs. on thunderstorms. Thunder storms come from the 

 west at Washington — on the opposite side of the river divide, 

 one part down, the other to Baltimore. Prepare circulars 

 relative to storms of this kind." 



The "Instructions for Meteorological Observers" were writ- 

 ten by his own hand. The instruments for distribution were 

 tested by him, and that magnificent corps of observers whose 

 contributions, covering a period of thirty years, constitute 

 a considerable portion of the foundation of meteorological 

 science, was kept together by his personal labor in corre- 

 spondence. 



His original study was not limited, however, to electricity 

 or to physics. He entered every field into which human 

 thought may enter. 



He was, perhaps, the first to work out a theory of the cor- 

 relation of physical, chemical, and vital forces. This was in 

 1844. His conclusions were essentially as follows: ^ 



"They who are disposed to continue the speculation . . . 

 may extend the generalization so as to reduce all mechanical 

 motion on the surface of the earth to a source from without. 

 Thus . . . the mechanical power exerted by animals is due 

 to the passage of organized matter in the body from an un- 

 stable to a stable equilibrium [or, as it were,] (from the combus- 



"^ Proceedings of the American Philosophical page 215; The London, Edinburgh, and 

 Society, 1844, Volume iv, page 127; Anier- DuUin Philosophical Magazine, 1845, Vol- 

 ican Journal of Scietue, 1845, Volume XI.VIII, ume xxvi, page 541. 



