13:2 Boyal Instliuiion. 



acid, and there are other analogous substances. Mr. Jahn 

 Davy considered the whole lenour oF these experiments as 

 ofForing conlirniations of the fact that oxymiiriatic jras, or 

 chlorine, has not yet been decompounded, and that it is a 

 solvent and acidifying principle analogous to oxygen. 



KOYAL INSTITUTION. 



ISIr. Davy's Lectures on the Elements of Chemical 

 Philoiophy. 



Mr. Davy delivered his second lecture on Saturday, Feb. 

 tlie first. He offered some general views concerning the 

 different modifications of matter, and the active powers en- 

 gaged in the production of the phaenomena of nature and 

 of art; he then directed the attention of his audience to 

 licat, or calorific expansion. He considered its important 

 and diversified agencies in the oeconomv of things; and after 

 an elaborate discussion concerning the mechanical and che- 

 mical hypotheses relative to the nature of heat, he conckided 

 by defining the limits of our knowledge on the subject. 



The ex]iansive cnenjiv, or power of repulsion producing 

 h.eat ; and attraction, which is cither gravitative, chemical, 

 or electrical, being one of the active powers belonging to 

 matter, which cannot be separated from it — matter itself 

 may be considered as inert, and all the harmonious arrange- 

 ments in the heavens and the earth may be regarded as 

 flowing from one primary cause, which, as it is intelligent, 

 says Mr. Davy, must be divine. 



The Professor entered into particular details relative to 

 the effects of heat, its importance, and the laws of its ope- 

 rations. The law of expansion is connected with the equali- 

 zation of the temperature of the slobe, the production of 

 winds, and the preservation of animal and vegetable life. 

 He particularlv pointed out its application to the ventilation 

 of mines, and the heating and ventilating of rooms. He 

 exhibited a model, illustrating the- manner hv which the 

 House of Lords is ventilated and warmed, after a new plan 

 proposed by himself. Ail the air deteriorated bv respiration 

 or combustion in the house, finds a ready exit by means 

 of three copper pipes carried to the roof, and ultimately 

 meeting in a single pipe ; the circulation of the air is assisted 

 by a furnace, and bv means of ventilators below there is a 

 constant supply ol fresh air. Such a plan Mr. Davy con- 

 ceives might be adopted in large drawing-rooms, or in 

 crowded assemblies, with excellent effect and at a trifling 

 expense. 



The 



