CONTENTS. xx { 



with increase of temperature. Depends on increased resistance to con- 

 duction. Quantity of electricity independent of heated surface. In 

 thermo-electric piles the quantity of electricity is proportional to 

 the number of pairs. Best forms of construction of thermo-electric 

 pairs Page 324 



MEMOIE XXV. 



ON MICROSCOPIC PHOTOGRAPHY. 



Method of making microscopic photographs by condensed sunlight. 

 Specimens of the-art 338 



MEMOIE XXYI. 



ON CAPILLARY ATTRACTION AND INTERSTITIAL MOTIONS. THE 



CAUSE OF THE FLOW OF SAP IN PLANTS AND THE 

 CIRCULATION OF THE BLOOD IN ANIMALS. 



Interstitial motions of solids. Motions of metal in coins. Movement of 

 liquids in crevices. Capillary attraction. Conditions for a continu- 

 ous flow. Capillary attraction an electrical phenomenon. Motions 

 of liquid conductors. Dutrochefs experiment of endosmosis. Pas- 

 sage of gases through liquids. Soap bubbles. Passage against heavy 

 pressure. Distribution of sap in plants. Circulation in plants due to 

 sunlight producing gum. Circulation of blood in animals explained. 

 The systemic, the pulmonary, and the portal circulation 342 



MEMOIE XXVII. 



ON THE EXISTENCE AND EFFECTS OF ALLOTROPISM ON THE CON- 

 STITUENTS OF LIVING BEINGS. 



Allotropism of elementary substances. Frankenheim? s nomenclature. 

 Brought about by light, heat, electricity, and by the nervous principle. 

 Explanation of inflammation and congestion 375 



MEMOIE XXVIII. 



ON THE DISTRIBUTION OF HEAT IN THE SPECTRUM. 



Early experiments seeming to prove that the maximum of heat is in the 

 less refrangible spaces. Comparison of the dispersion and diffraction 

 spectra. Effect of compression in the less refrangible regions and of 

 dilatation in the more refrangible. Measure of heat in the two halves 

 of the visible dispersion spectrum. Description of the apparatus em- 

 ployed. The different colored spaces are equally warm 383 



