279 



von Miiller, Director of the Gardens at Melbourne, who 

 recognized about one hundred and fifty species or varie- 

 ties of Eucalyptus, many of large size, some growing 

 grandly on arid plains, others on Australian " Alps " and 

 " Pyranees " at various elevations ; the highest mountain 

 summits being not above 7000 feet over sea level. Some of 

 these mountain kinds will probably grow in Philadelphia, 

 and he will be happy to assist their introduction. He had 

 seen large plantations of Eucalyptus between St. Jose and 

 San Francisco, and others growing in the interior. He had 

 come to the conclusion in his own mind many years ago 

 that the fragrance diifused through the Australian atmos- 

 phere by the essential oils of these trees must account in 

 part for the remarkable immunity which settlers and trav- 

 elers, however exposed at night in the bush, had always 

 enjoyed against malarious fevers, although the climate was 

 as hot as in malarious districts of Italy. No malaria was 

 known, although low typhoid fevers were not unknown. 



Mr. Davenport remarked the great difference between the 

 vegetation of Adelaide and Philadelphia, and had been 

 much impressed by the exuberant foliage of the Park 

 around the Centennial grounds. 



Prof. Houston reported the result of his proposed experi- 

 ment with the 19" Fresnel lens through which, about two 

 weeks ago, he had concentrated the beams of a full moon in 

 a spot of about a quarter of an inch diameter, on the flags 

 of a Crooke's radiometer, without obtaining the least move- 

 ment ; whereas the same instrument, at the same time, was 

 moved by the heat of boiling water in a glass tube, but was 

 not sensitive to radiant heat below about 212°. In a room, 

 however, the heat of the hand would move it, a lighted 

 match would make it move swiftly, even the dull red glow 

 of the extinguished end of a match gave a sensible motion. 



Pending nominations 793 and 803 were read. 



And the meeting was adjourned. 



