320 



Royal Society : — 



in oxygen, and passing the products of the combustion into lime- 

 water, a copious precipitate of carbonate of calcium was obtained. 



On the Effects of Fusion upon Emeralds and Beryls. 



On the Effects of Fusion upon Opaque Beryls. — In order to study 

 the effects of fusion upon beryls or emeralds, I found it necessary 

 to use the oxyhydrogen blowpipe. Beryls and emeralds were 

 amongst the numerous substances fused with this instrument by 

 Clarke * as long ago as 1816. He states that the Siberian beryl 

 fuses to a clear glass containing bubbles. The Peruvian emerald 

 he found to melt very easily to a round, extremely beautiful bead 

 free from bubbles ; it lost its green colour, and became like a white 

 sapphire. 



My first experiments were made upon the beryl A ; it weighed 

 62-54 grms., and its density was taken with great care previous to 

 fusion. In the first experiment the whole crystal was suspended 

 from the balance-pan, and weighed in water ; in the second a few 

 fragments were weighed in a E-egnault's flask with the usual pre- 

 cautions. The values obtained were as follows : — 



Specific Gravity of Beryl A before fusion. 



No. ofexperi- w 

 ment. w ' 



W. 



t. 



pt. 



B. 



I. 

 II. 



62-5400 

 1-6838 



39-0000 

 1-0512 



o 



21-5 

 20-0 



•997936 

 •998259 



2-65 

 2-66 



In order satisfactorily to submit beryls to the action of the 

 oxyhydrogen blowpipe, it was necessary to find a support capable 

 of enduring the high temperature without burning away too ra- 

 pidly, and also not containing sufficient inorganic constituents to 

 complicate the results. After a few trials I selected square prisms 

 of gas-retort carbon, taking care to ascertain by experiment that 

 they were adapted to the purpose. Some specimens burn away 

 very readily ; and others yield too much ash to permit of their being 

 employed successfully. The oxyhydrogen blowpipe employed was 

 of the ordinary construction, and, with the exception of having 

 several nozzles of various calibres to adapt it to different quantities 

 of the substance to be experimented upon, needs no particular de- 

 scription. These nozzles (which supply the oxygen) should be well 

 formed, and free from internal irregularities. Instead of hydrogen, 

 coal-gas was generally employed, as I have not found, for the pur- 

 poses described in this paper, hydrogen to possess advantages suffi- 

 cient to counterbalance the inconvenience of storing it in the large 

 quantities required. 



The phenomena observed on submitting a fragment of beryl to 

 the action of the flame are very beautiful ; but to obtain the best 

 results, many precautions and some little practice are necessary. 

 * Sehweigger's Journ. vol. xviii. p. 237 (1816). 



