96 



Descriptive Characters of 



light charcoal points in a galvanic battery, and the light 

 of the sun. 



Now, although we do not know by what property of the 

 eye rays less refrangible than the extreme red become invisi- 

 ble, yet this \yill appear on inspection to be a wise arrange- 

 ment of Providence. 



For if the rays which emanate from bodies at ordinary 

 temperatures were invisible they would overpower those 

 exquisitely beautiful colours of nature which are produced by 

 reflection of the solar hght; besides which, there would be 

 no such thing as darkness, even when the eye was closed, for 

 light would still issue from the eyelids. And again, if rays 

 did not become visible till at a much higher temperature than 

 600^, combustion would go on in darkness, and we should 

 never be warned of the presence of fire. 



Finally, if we suppose a number of bodies (for simplicity's 

 sake spheres) to have been originally at the same temperature, 

 it is clear, that since radiation will vary with the surface 

 exposecl, large spheres, the surface of which bears a less 

 proportion to their solid contents than that of smaller ones, 

 will cool more slowly than smaller ones; so that at any given 

 time a large sphere would be at a much higher temperature 

 than a small one, and would, consequently, emanate visible 

 rays, Avhile the rays of the other would be invisible. 



Therefore, in a system of bodies, such as the solar system, 

 the centre of attraction is also the centre of illumination 

 which is a most wise and beneficial arrangement. 



Akt. XI. — Descriptive Characters of Neto Alpine Plants, 

 from Continental Aicstr alia. Dr. Fekdixand Mueller. 



In offering this small, yet perhaps not unwelcome contribution 

 towards the botany of Australia, I wished to conclude the 

 precursory diagnostic notes on our Alpine flora, of which 

 some scattered fragments appeared in this journal, and in the 

 papers of the Victorian Institute.* 



* The plants tltere enumerated and described are the following : — Eriostemon 

 lancifolius, P. phylicifolium, Phebaliuin ozothamnoides, Ph. podocarpoidos, ( Vo^^'ea 

 exalata, Scleranihus miaroidcs, Kunzca ericlfoha, Burtona subalpina, Oxylohium 

 alpestre, Bossisea distichoclada, Eurybia inegalophylla, Enrybia alpicolo, ]Jradiy- 

 como, multicanlis, Br. nivalis, Antennaria nubi<rona, Gnaphalium alpigenurn, 

 Agrostis nivalis, Agr. ^ frigida, Agr. gelida, Danthonia robusta, Hierochloe 

 submutica, and Astelia psychrocharis, A few aa doubtful remained yet 

 uncbaract erized . 



