Improved Laboratory Appliances. 409 
analytical process as Bunsen's method is for the determination 
of nitrogen in organic substances, no chemist would adopt it 
in cases where Will and Yarentrapp's less beautiful, hut easier 
and speedier method, could be employed ; for, as already 
stated, analytical operations are only a means to an end, and 
the speedier, with accuracy, chemists can arrive at results, the 
more conducive it must be to the progress of the science. 
At the present time a great deal of labour is involved, and 
time wasted, by having to set up in a laboratory, where a 
variety of work is going on, so many distinct pieces of apparatus, 
each requiring to be started separately. For obtaining the 
indispensable distilled water, a special still and heating- appa- 
ratus is generally set apart for the purpose. Distillation under 
diminished pressure is another distinct, and frequently trouble- 
some, operation. If a filter-pump is employed to hasten filtra- 
tion, the pump is solely devoted to that purpose. Then there 
are the open and closed water-baths, each distinct and requiring 
a separate heating-apparatus ; and for heating and drying 
substances above 100° 0. the methods are most inconvenient. 
But of all the slow methods, that of evaporating by means of 
the ordinary air-pump and absorbing the water as it evapo- 
rates by means of sulphuric acid is, we think, the slowest. 
The appliances that are in use generally for forcing steam, air, 
or gases over substances are, to say the least, inconvenient. 
By the aid of a small general air-pump connected to a little 
stationary engine, and ordinary or superheated steam, all these 
operations can be carried on at the same time with these ap- 
pliances excepting the one last described ; for this operation 
there is required, in addition to the air- or suction-pump, a 
compression-pump in connexion with the engine. 
In carrying out some researches recently we found great 
convenience and saving of labour and time in employing a 
general air-pump. This has led us to devise appliances for the 
extension of our plan to a larger number of chemical operations, 
which we will now describe, as we think the arrangement 
will be found very useful not only in educational laboratories, 
but also in pharmaceutical laboratories, especially in the pre- 
paration of delicate organic compounds. 
The boiler A (Plate VII. fig. 1) we recommend is Cochran's 
patent multitubular vertical boiler with internal fire-box and 
horizontal tubes, because it is the boiler, in our opinion, which 
gives the maximum heating-surface for the space occupied : a 
boiler 2 feet in diameter and 2 feet 6 inches high will afford, 
for example, sufficient steam to work a one-horse-power engine. 
No brick setting or brick chimney is required ; and the top 
can be removed, so that the interior of the boiler can be 
