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CONTE 
O F 
VOL. LXXVIII. Part L 
I. /JjP the Methods of manfefling the Prefence , and afcertaining 
the Quality, of frnall Quantities of Natural or Artificial 
FleElricity . By Air. Tiberius Cavallo, F . R. S. Page 1 
II. The Croonian LeEiure on Mufcular Motion . George For- 
. dyce, M. D. F. R. S. p. 23 
III. An Account of a Mafs of native Iron, found in South- America, 
By Don Michael Rubin de Celis. Communicated by Sir 
Jofeph Banks, Bart. P. R. S. P- 37 
IV. Frigorific Experiments on the mechanical ex- 
pansion of Air, explaining the Caufe of the great Degree of 
Cold on the Summits of high Mountains , tire fudden Condenfa- 
tion of aerial Vapour , and of the perpetual Alutabihty of 
atmojpheric Heat. By Erafmus Darwin, A I. D. F. R. S. ; 
communicated by the Right Honourable Charles Greville, 
F. R. S. p. 43 
V. Some Obfervations on the Heat of Wells and Springs in the 
Jjland of Jamaica, and on the Temperature of the Farth 
below the Surface in different Climates. By John Hunter, 
AI. D. F. R. S.', communicated by the Hon, Henry Cavendifh, 
F. R. S. p. 
VI. 
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