326 



Proceedings of Societies. 



one uniformity, tlie earth's circumference line would occupy a position 

 nearly 5000 feet helow the present ocean level. But as water is only 

 about half the specifie gravity of the materials composing the superficial 

 strata of the earth, twice the volume of water is thus necessary to fill up 

 the depressions and to bring about that equilibrium which is required. 

 In looking, therefore, at a section of the earth's surface, constructed 

 according to the above measurements, it will at once be seen how small a 

 proportion the mean elevation of land bears to the mean depth of the 

 ocean — that while the extremes of both are nearly equal, the extreme 

 elevation of mountains equalling the extreme depressions of ocean — the 

 ocean surface occupies a level half way between these extremes, and thus 

 becomes the actual line of circumference. But then its surface is thus 

 raised from the true central line of the earth's inequalities, in consequence 

 of the less relative specific gravity which water bears to the superficial 

 strata of the earth's crust. There would appear also to be this general 

 arrangement in the seeming irregularities of the earth's surface, that the 

 depressions of the sea bottoms accompany and compensate the elevations 

 of continents, and thus preserve the due equilibrium of the rotating 

 spheroid. Thus the Atlantic is a great hollow basin between the elevated 

 continents of Asia and Africa on the east and America on the west ; while 

 the deepest portions of the Pacific are on the west side of the American 

 continent, and its central portions are comparatively shallow. Even in 

 inland seas, the depths of the Mediterranean, ranging from 5000 to 15,000 

 feet, correspond with the elevations of Mont Blanc and the Alpine range, 

 while the shallow Baltic and North Sea are surrounded by lands of no 

 great elevation. We thus find in the great operations of nature that 

 adaptation of means to ends which pervades the whole works of creation, 

 and which are as perfect in the arrangements of the mechanism of worlds 

 as in the minutest objects which exist on their surfaces. 



Botanical Society of EdinhurgJi. 



Thursday, lUh January 1864. — Professor Balfour, President, 

 in the Chair. 

 The following Communications were read : — 



I. New Researches on Hyhridityin Plants. By M. Ch. Naudin. Part I, 

 Translated from the French, and communicated by Mr George M. 

 Lowe. 



(This paper appears in the present number of the Journal.) 



II. Letter from Robert Brown, Esq., Botanist to the British Columbia 



Association. Communicated by Professor Balfour. 



Valley of the Ses-haat Indians, Barclay Sound, 

 Vancouver Island, 

 Lat. 48° 47' 28", Nov. 4, 1863. 

 Though I will be in Victoria about ten days after this date, when I 

 will write you a full account of my transactions for the last three months, 

 yet the politeness of the master of a trading schooner enables me to save 

 a mail, and inform you that I am still in life and at work. Since I last 

 wrote I have been to Washington Territory, U. S., British Columbia, 

 and I have (first of white men) reached the head of the " great" central 

 lake of Vancouver Island — that ignis fatuus of the local geographers 

 of this far western portion of her Majesty's dominions. I have ob- 

 tained seeds of between one and two hundred species of plants (in almost 



