1815.] the Uiine contains no Urea. ■ 427 



luted into the bottle ; perhaps putty is the best lute. The jar is 

 filled with cold water as a refrigerator ; but the principal agent in 

 condensing the vapour is a glass syphon (and so efficient is it, that 

 the condensed vapour falls guttatim into the receiver). It is placed 

 so as to convey cold water on to the tube which connects the retort 

 with the receiver, and this, trickling along it, is received by a large 

 bason, in which the jar and bottle stand. The tube may be luted 

 to the flask and bottle with a stiff dough of flour and water. If the 

 lute is not carefully, and in sufticient quantity, aj)plied around the 

 tube where it passes into the cork of the receiver, the water from 

 the syphon will wash it away, and into the receiver, making the 

 liquid cloudy, and oblige you to repeat the process, llie longer 

 the tube is to convey the vapour, and the larger its calibre, the 

 better it is for your purpose. The calibre of the syphon may be 

 between a twelfth and a sixteenth of an inch in diameter. These 

 tubes may be bent in any form, with the assistance of a lamp and 

 blow-pipe, or a blacksmith's fire. Fearful that my description of 

 the still which 1 have been in the habit of using is not sufficiently 

 clear to enable any body to construct one by it, I have subjoined 

 a rough sketch ot it as it appears when in use. The readiness with 

 which its materials may be had, the ease with which it may be 

 constructed, and the convenience of such a simple apparatus to the 

 juvenile experimentalist, are things which I hope will in some 

 measure repay you for giving the above tedious description, and the 

 following sketch, a place, which might have been occupied by 

 something of more importance. 



I remain, Sir, yours most respectfully, 



C. B. Rose. 



o, the Florence oil-flask ; I, ihe bottle, as the receiver ; c, t}^e 

 JHT in which the bottle is fixed; d, the barometer tube to convey 

 the va|Kjur; r, the jug of cold water j^i the glass syphon ; g, the 

 bafon ill which the jar stands. 



