108 



Historical Society of the American Lutheran Chui-ch, May 18^ 

 1848. By William M. Reynolds, A.M. Professor in Pennsylvania 

 College, Gettysburg, Pa. 8vo. — From Professor M. L. Sfoever, 

 of Gettysburg. 



The Study of Natural History. An Address delivered before the 

 Linnsean Association of Pennsylvania College, at the Annual 

 Commencement, Sept. 19, 1849. By Daniel M. Smyser, A.M. 

 Gettysburg, 1849. 8vo. — From the same. 



The Pennsylvania Journal of Prison Discipline and Philanthropy. 

 Vol. IV. No. 4. Oct. 1849. Philadelphia. 8wo.— From the 

 Philadelphia Prison Society. 



The African Repository and Colonial Journal. Vol. XXV. No. 10. 

 Oct. 1849. Washington. 8vo. — From the American Coloniza- 

 tion Society. 



Mr. Justice mentioned to the Society, that within a few 

 weeks past he had had placed in his hands for examination, a 

 telescope, the object-glass of which had been affected by the 

 deterioration before alluded to by him. In this case the im- 

 pression from one of the lenses of the object-glass had been 

 communicated to the other lens. 



Professor Henry communicated some experiments which he 

 had made upon the subject of the radiation of heat. It occurred 

 to him, from the constitution of the atmosphere, that if the air 

 was a good radiator of heat, the higher temperatures below, 

 and lower above, could not be permanent. By placing a 

 thermo-multiplier before a flame, interposing a screen of wood 

 with a hole through it, radiation from the flame was perceived, 

 becoming less as the flame was lowered, and still existing, 

 though in small quantities, from the heated air above the flame. 

 Prof. H. also repeated the experiments upon the radiation of 

 heat from flames. The radiation of heat from the flame of 

 hydrogen is but small, as is its radiation of light. This radia- 

 tion is much increased by placing a solid in the flame. This is 

 in accordance with Count Rumford's assertion, that clay-balls 

 placed in the fire increased the amount of heat. Prof. Henry 

 also mentioned some experiments which he had made some 

 years ago upon the reflection of heat from ice with a concave 

 mirror of that substance. 



