1873.] Mr. Greville Williams on Emeralds and Beryls. 415 



ing of the emeralds and beryls, I pulverized some emeralds in a porcelain 

 mortar, every precaution I could devise being taken to prevent any con- 

 tact of organic matter. On burning 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 con- 

 taining 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 B-egnault's flask with the usual precautions. The values 

 obtained were as follows : — 



Specific Gravity of Beryl A before fusion. 



No. of experi- 

 ment. 



W. 



W. 



t. 



pt. 



D. 



I. 

 II. 



62-5400 

 1-6838 



39-0000 

 1-0512 



x o 



21-5 

 20-0 



•997936 

 ' -998259 



2-65 

 2-66 



In order satisfactorily to submit beryls to the action of the oxyhy- 

 drogen blowpipe, it was necessary to find a support capable of enduring 

 the high temperature without burning away too rapidly, 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 blow- 

 pipe employed was of the ordinary construction ; and, with the exception 

 of having several nozzles of various calibres to adapt it to different quan- 

 tities 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 purposes 



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



