36 On the Rapid Estumation of Urea. 
the bottle, the generating vessel is complete. When an cstimation 
is in progress the bottle A is placed in a tumbler T (or beaker), 
containing cold water at a temperature of 52° ¥., as nearly as 
possible. 
The gas receiver.—This is easily constructed from a large pipette 
whose bulb F is capable of containing about three fluid ounces. 
The tube fis cut off so as to admit of being securely joined to the 
tube E of the generating vessel] by means of an india-rubber 
connector. The delivery tube is then bent, as shown, and at the 
point H a little hole is made. A groove cut in a block of wood 
g receives the bent tube of the little gas holder, which is then 
easily secured in its place by any suitable cement—common 
sealing wax, forexample. Thus, with the aid of the two pipettes, 
cork, and tubing, which can be easily procured through a druggist 
for about 3s., a medical man can construct his own ureometer.* 
When in use the block g is secured to the board 8 on which 
the beaker T stands held by the wire W. 
Mode of using the Apparatus—The vessels A and F are dis- 
connected, and F filled with water until it overflows and the excess 
has ceased to drip from the tube under H. The cork is removed 
from the bottle A, and two fluid drachms of the liquid to be tested 
measured off in a tall minim measure, and then poured into A; 
one drachm of water is next used to rinse the liquid adhering to 
the sides of the measuring glass into the bottle A; the total 
volume in A therefore should measure about three drachms.t For 
a reason which will presently appear, it is desirable that no more 
water than one drachm should be employed. If a pipette deliver- 
ing two drachms be used, a drachm of water should be added; 
but the pipette need not be rinsed with it. The next step is to 
fill the pipette B with the re-agent which evolves the nitrogen of 
the urea. For this purpose a suitable vessel—a wine-glass for 
example—is filled with the hypobromite liquid ;t the forceps D 
* Messrs. Yeates & Son, of this city, supply a neat form of my apparatus ready for use. 
+ The measures used should be good, the two-drachm and two-ounce vessels agreeing 
with each other. The amount of reliance which can be placed upon the results depends 
in great part on the accuracy of tbe measures. 
t This solution is prepared as follows:—Dissolve 4 ounces of the solid caustic soda of 
the shops in 10 fluid ounces of water. When the soda has dissolved and the liquid cooled 
to 60° F., add gradually 1 fluid ounce of bromine. The test solution is then ready for 
use. It should be kept in a cool place, and away from the light. 
