302 Proceedings of Philosophical Societies. [April, 



Utilization, and that the peculiarities which characterize each of 

 them are to be considered as of a similar description with those 

 local differences observable in crystallizations from the same 

 solution. But the geognostical distributions of simple minerals 

 are very different from those of mountain rocks : we do not find 

 the same species every where ; on the contrary, they seem to have 

 many kinds of distributions, in this respect approaching more 

 nearly to what we observe in the physical arrangement of animals 

 and vegetables over the face of the earth. Professor Jameson 

 entered very particularly into this interesting subject. At the 

 same meeting, Professor Jameson read some observations on the 

 natural history of the diamond, and stated it as a conjecture 

 that the remarkable hardness of some woods may be owing to 

 their containing carbonaceous matter, approaching to the ada- 

 mantine state, and that the diamond itself might occur as a 

 secretion in grain, or even in crystals, in some of the vegetables 

 in the warmer regions of the earth. He also alluded particularly 

 to the natural history of the tabasheer, or vegetable opal, found 

 in some oriental vegetables ; and from the great tendency ob- 

 served in some vegetables to secrete silica, he offered, as a 

 conjecture, that some silicified woods met with on the surface of 

 the earth might be trunks, or branches of trees, which had been 

 killed by the over secretion of siliceous matter. 



At the same meeting the Secretary read a communication 

 from Mr. Butter, surgeon of the South Devon Militia, giving an 

 account of the change of plumage in the females of several galli- 

 naceous birds, particularly common poultry, to that which 

 resembles the males ; and showing that this is a natural result of 

 advanced age only, and not to be accounted a monstrosity. 



At the meeting on Jan. 24, Mr. James Wilson communicated 

 some remarks on the eggs of the common frog, and on the tad- 

 pole in its early state, tending to prove that the young animal 

 derives its nourishment from the mass of gelatinous matter with 

 which it is encompassed, and that by means of a filament, analo- 

 gous to an umbilical cord, by which it is attached to the mass. 

 Mr. Wilson also gave an account of the progressive develop- 

 ment of the members or extremities of the animal, as observed 

 by him. At the same meeting, Mr. Alexander Adie, optician, 

 exhibited and explained his new instrument called the sj/mpieso- 

 meter, or measurer of compression ; in which the moveable 

 column consists of oil, including in a glass tube a portion of azote, 

 which changes its bulk according to the density of the atmo- 

 sphere. The barometric scale is made to slide up and down, so 

 that it can be adjusted to a Fahrenheit's thermometer attached 

 to the instrument. 



Feb. 7.— The Secretary read the first part of Dr. Traill's ac- 

 count of an African orang-outang, which lately died at Liverpool, 

 the property of Mr. Bullock of the Piccadilly museum. In the 

 introduction to his paper, he gave an account of the manners of 

 the animal, as described by Captain Payne, who purchased it 



