312 Scientific Intelligence, [Oct. 



III. Elastic Gum Bougies; and a Method of separating Ether 



from Water. 



(To Dr. Thomson.) 



Eye, July 19, 1814. 



In Number XIV. of your Annals of Philosophy, a Correspondent 

 expressed a wish to know how elastic gum bougies are made ; some 

 friend in Number XVI. communicated a method of constructing 

 the elastic gum catheters : now there is no doubt that bougies are 

 made in a similar manner 5 but as the instruments are not alike, so 

 the materials also differ. 



I have had occasion to cut the elastic gum bougies in pieces, and 

 the appearance of the divided part always gave me an idea that they 

 Were the catgut bougies covered with caoutchouc. To satisfy myself 

 more of this, I prepared some ether, as directed by Mr. Winch, of 

 London (and described in Dr. Henry's Elements of Experimental 

 Chemistry) ; 1 then suspended a portion of a caoutchouc bougie in 

 it, and after a time the gum was dissolved, leaving the catgut bare. 

 Where, or how, they are constructed, 1 do not know; but I think 

 it likely they are made by dipping catgut bougies into a solution of 

 the caoutchouc, in the same manner as dipped candles are made. 

 .Dr. Henry informs us, " That the method of forming tubes, &c. 

 with this solution is described in the first volume of Fauja's Travels 

 in England, Chap I." 



While preparing the ether for the above experiment, and the 

 ether and water having been put into a vial so that it was about half 

 full, I felt at a considerable loss how to separate them, until I con- 

 trived the following simple apparatus, the principle of which your 

 readers will readily perceive. I passed a small short glass tube 

 (whose calibre would not allow the fluid to pass) through the cork 

 of a vial, and just even with the opposite end of the cork ; I then 

 turned the bottle upside down, and, allowing time for all the pure 

 ether to rise to the surface of the water, then took a red-hot poker 

 and applied it to the bottom (now the upper end) of the vial, which, 

 expanding the air, drove the water out of the bottle. This method 

 of separating water from ether 1 have transmitted to you, for the 

 purpose of communicating it to those of your readers who, like me, 

 have not the means of getting proper chemical machines. 



Should you think the above mites of information deserving a 

 place in your Am\uU of Philosophy, the insertion of them will 

 much oblige 



Yours mpst respectfully, 



C. B. Rose. 



IV. Diminution of Tumperalurrfrom Rain. 



(To Dr. Thomson.) 



WiR, 



The Number of the Annals of Philosophy for August contained 

 S notice respecting a remarkable fall in the thermometer which 



