354 Fluoric Acid of Gay Lussac. 



Akt. XXII. — Fluoric Acid of Gay Lussac, and its application 

 to the etching of glass. — Editor. 



As we have not seen any notice, that this powerful acid 

 has been obtained in this country, we will briefly mention, 

 that we procured it in full strength, during the late winter, and 

 comparing it with the account given in the memoir, in the 

 ''Recherches Physico-Chimiques," of Messrs. Gay Lussac 

 and Thenard, observed with much satisfaction that its prop- 

 erties fully justify their statement; not that we think their 

 researches or those of Sir. H. Davy, needed confirmation, 

 but, notices of interesting facts by different persons especially 

 in different countries are not without utility. 



The leaden apparatus, recommended for procuring pure 

 fluoric acid, we have found so liable to fusion, and besides 

 the failure of the experiment, and the loss of the apparatus, 

 the fumes are so noxious and even dangerous, that we were 

 induced to resort to the use of vessels of pure silver. For this 

 purpose, an alembic* was made of the capacity of 16 fluid 

 ounces, with a head and tube of the capacity of two and a 

 half, and the tube was made to fit accurately the mouth of a 

 silver receiver of the capacity of three and a half ounces. 

 The latter (see the apparatus represented at fig. 7, plate 10.) 

 was made, in the form of a bottle, and furnished with a sil- 

 ver stopper, ground so as to fit air tight ; it being intended to 

 serve, both as a receiver, and a containing vessel, for the 

 acid, thus obviating the necessity of transferring it into 

 another vessel. 



Two ounces of very pure fluor spar from Shawneetown 

 were introduced into the alembic, and four ounces of sul- 

 phuric acid were added ; there should be no excess of acid, 

 lest it should attack the silver. The whole apparatus was 

 placed under a flue; the receiver was kept cold by ice, and 

 a few live coals being applied beneath the alembic, served 

 to disengage the acid, which was condensed in the receiver. 

 without the aid of water. 



* The alembic was made thick and heavy, and furnished with a silver 

 cap, so that it might be used without its head, as a large crucible. 



The cost of the entire apparatus, alembic-head, tube, cap and receiver,. 



was about sixty dollars. 



