462 Dr. Ure on the ultimate analysis of 
quantity, hitherto ill appreciated or neglected in many ex- 
periments, though it is of very great consequence, may be 
accurately found. At k, fig. 2, a little tin-plate screen is 
shown. It is perforated for the passage of the tube, and 
may be slid along, and left at any part of the semi-cylindric 
cage, so as to preserve from the influence of the heat, any 
requisite portion of the sealed end of the tube. At fig. 4 is 
seen the shape of the little bulb, into which I introduce the 
proper weight of ether, alcohol, naphtha, or other volatile 
liquids, which are destined for analysis. After weighing it 
exactly, it is immediately slid down to the bottom of the tube, 
and covered with 150 or 200 grains of peroxide of copper. 
The bulb has a capacity equal to 3 grain measures of water, 
and its capillary point is sometimes closed with an inappreci- 
ably small quantity of bees wax, to prevent the exhalation of 
the liquid, till the peroxide be ignited. 
b is a cover to the furnace, with an oblong orifice at its top. 
It serves for a chimney, and may be applied or removed by 
means of its handle, according as we wish to increase or 
diminish the heat, c c are tin cases inclosing corks, through 
which the iron wires are passed, that support the whole fur- 
nace at any convenient height and angle of inclination. 
The tightness of the apparatus at the end of the process, is 
proved by the rising of the mercury in the graduated receiver, 
by about one-tenth of an inch, as the tube becomes re- 
frigerated. 
My mode of operating with the peroxide of copper is the 
following : 
I triturate very carefully in a dry glass mortar, from 1 to 2-§- 
grains of the matter to be analyzed, with from 100 to 140 
