RECOMMENDATIONS. 475 



the manner of its transmission in such cases is strictly analogous 

 to that in which light is commvinicated ; or is it only an ex~ 

 tremely rapid communication by conduction ? What circum- 

 stances can be fixed upon to determine our view of the matter? 



4. Taking into account the thickness, state of surface, &c., 

 of a body exposed to radiant heat, does any portion of time 

 elapse before it acquires heat from the source ; or before it 

 begins to radiate it again, when acquired ? and how soon will 

 it commence radiating on the opposite side ; or according to what 

 law does the heat distribute itself over or through the body ? 

 These questions are put in reference chiefly to the action of 

 the body as a screen, and to the possibility of accounting for 

 an apparently direct transmission of heat without the necessity 

 of supposing any other principle than that of conduction. 



5. What are the modifications which radiant heat undergoes 

 in passing through small apertures ? (p. 299.) 



6. Sir J. Leslie found that the focus for simple heat, in the 

 concave reflectors he used, was different from and nearer to 

 the reflector than that for light : Is this confirmed by more 

 extensive and exact observations? and what is the precise focal 

 distance in different cases ? (Leslie's Inquiry, p. 14.) 



7. What is the proportion of heat reflected at different in- 

 cidences ? 



8. What radiation takes place in vacuo ? (p. 300.) 



CHEMISTRY. 



\. That British Chemists be invited to make experiments 

 for removing doubts respecting the proportions of Oxygen, 

 Azote, &c., in the atmosphere; for determining the proportions 

 of Azote and Oxygen in Nitrous Gas and Nitrous Oxide ; and 

 for more accurately investigating the specific gravity of the 

 compound gases in general. 



2. That Dr. Dalton and Dr. Prout be requested to institute 

 experiments on the specific gravities of Oxygen, Hydrogen, 

 and Carbonic Acid, and that a sum not exceeding 50/. be ap- 

 propriated to defray the expense of any apparatus which may 

 be required. 



3. That Dr. Turner' be requested to extend his researches 

 into the atomic weights of the elementary bodies, and to re- 

 port on the progress recently made in this branch of chemical 

 science. 



' Dr. Turner ruporlcd llie progress of his researches to the Meeting at 

 Cambridge. 



