and physical properties of tahasheer. 295 
Grains. 
No. I. Seven pieces of opaque tabasheer, 
weighed in air. - - 665 
The same pieces when thoroughly 
soaked in water, weighed in air - 14,10 
The same weighed in water at the 
temperature of 52 0 - - 3,42 
Hence the specific gravity of the parcel when dry , is 2.059 
And the specific gravity of the parcel when wet, is 1.320 
Grains 
No. II. Several small fragments of trans- 
parent tabasheer, weighed in air - 1 ,23 
The same pieces when thoroughly 
soaked in water, weighed in air - 2 ,54 
The same weighed in water at the 
temperature of 52 0 - - 0,72 
Hence the specific gravity of the parcel when dry, is 2,412 
And the specific gravity of the parcel when wet, is 1,396 
Mr. Macie found the specific gravity of a parcel of opaque 
and transparent tabasheer to be 2,188 ; and Mr. Cavendish, 
having tried the same parcel, found it to be 2,169. The mean 
of Mr. Jardine's results is 2,235, which exceeds the mea- 
sures of Macie and Cavendish, because the opaque frag- 
ments in their parcels must have been more numerous than 
the transparent ones, in consequence of the rarity of the 
latter. 
It appears from the preceding results, that in both kinds of 
tabasheer the quantity of water imbibed exceeds in weight 
that of the tabasheer itself ; and that in the opaque kinds, 
the space occupied by the pores is to the space occupied by 
the tabasheer, as 2,307 to 1 ; while in the transparent kinds, 
it is 2 ,5656 toi. This result indicates a very remarkable 
