VOL. LXXXI.] PHILOSOPHICAL TRANSACTIONS. 101 



XXII. Of some Chemical Experiments on Tabasheer. By James Louis Made, 



Esq., F. R. S. p. 368. 



The tabasheer employed in these experiments was that which Dr. Russell laid 

 before the Society, as specimens of this substance, the evening his paper on the 

 subject was read, and published in the Philos. Trans, vol. 80, p. 283. There 

 were 7 parcels. N° 1 consisted of tabasheer extracted from the bamboo by Dr. 

 Russell himself. N° 2 had been partly taken from the reed in Dr. Russell's pre- 

 sence, and partly brought to him at different times by a person who worked in 

 bamboos. N° 3 was the tabasheer from Hydrabad ; the finest kind of this sub- 

 stance to be bought. N° 4, 5, and 6, all came from Masulapatam, where they 

 are sold at a very low price. These 3 kinds have been thought to be artificial 

 compositions in imitation of the true tabasheer, and to be made of calcined 

 bones. N° 7 had no account affixed to it. The tabasheer from Hydrabad being 

 in the greatest quantity, and appearing the most homogeneous and pure, the 

 experiments were begun, and principally made, with it. 



Hydrabad tabasheer. (N° 3.) — § 1. (a) This, in its general appearance, very 

 much resembled fragments of that variety of calcedony which is known to mine- 

 ralogists by the name of cacholong. Some pieces were quite opaque, and ab- 

 solutely white ; but others possessed a small degree of transparency, and had a 

 bluish cast. The latter, held before a lighted candle, appeared very pellucid, 

 and of a flame colour. The pieces were of various sizes ; the largest of them 

 did not exceed -^ or ^3- of a cubic inch. Their shape was quite irregular ; some 

 of them bore impressions of the inner part of the bamboo against which they 

 were formed, (b) This tabasheer could not be broken by pressure between the 

 fingers ; but by the teeth it was easily reduced to powder. On first chewing it 

 felt gritty, but soon ground to impalpable particles, (c) Applied to the tongue 

 it adhered to it by capillary attraction, (d) It had a disagreeable earthy taste, 

 something like that of magnesia, (e) No liglit was produced either by cutting 

 it with a knife, or by rubbing 2 pieces of it together, in the dark; but a bit of 

 this substance, being laid on a hot iron, soon appeared surrounded with a feeble 

 luminous aureole. By being made red-hot, it was deprived of this property of 

 shining when gently heated ; but recovered it again, on being kept for 2 months. 

 (f) Examined with the microscope, it did not appear different from what it does 

 to the naked eye. (g) A quantity of this tabasheer which weighed 75.7 gr. in 

 air, weighed only 41.1 gr. in distilled water whose temperature was 52.5 f. 



with the management of the calcining process, it has been proposed by Mr. Chenevix (Phil. Trans, 

 for 1801) to obtain a similar product by the humid way, i. e. by dissolving together equal quantities 

 of sub-muriate of antimony and phosphate of lime, in as small a quantity as possible of muriatic acid, 

 and adding this solution gradually to water alkalized with ammonia. The precipitate thus obtained, 

 coincides in composition with James's powder. 



