ON THE PREPARATION OF SPIRIT OF NITROUS ETHER. 
511 
or by too greatly altering the character of the product. The London process 
failed from the first of these causes. The Edinburgh and Dublin processes 
have also equally failed from the latter causes, for as these processes consisted 
in the production of pure nitrous ether as a preliminary operation, by a some¬ 
what wasteful method more applicable to operations on the small than on the 
large scale, and the subsequent solution of the ether thus produced in spirit, in 
the one case in the proportion of one to four, and in the other, of one to ten, 
they have proved unsuited for the purpose of the manufacturer. 
In the British Pharmacopoeia of 1864 a new process was given for this pre¬ 
paration, under the name of spirit of nitrous ether^ and great expectations were 
at first formed with respect to it. I need hardly say that these expectations 
have been disappointed. So much has been published by myself and others with 
reference to nitrite of soda, and its proposed use in the manufacture of spirit of 
nitrous ether, that it will be sufficient for me to state here, that this process has 
brought us no nearer than we were before to a satisfactory and available method 
of accomplishing what is required. 
I have been engaged for a considerable time in submitting the various 
published processes for nitrous ether and sweet spirit of nitre to practical 
trial with the view of ascertaining which is the best, and have made a 
great number of experiments for the purpose of discovering a more satis¬ 
factory method of obtaining these products, and especially the latter one, 
than any of those hitherio adopted. I was anxious to find a process that 
would be suitable for the Pharmacopoeia, and which, at the same time, 
would commend itself to the manufacturer, so as to induce its general adop¬ 
tion. To fulfil this object it was essential that the process should admit 
of application without difficulty on a large or small scale, with similar and 
uniform results, yielding a product resembling the best sweet spirit of nitre 
of commerce, at a cost not exceeding that at which it could be produced by 
any other known process. In the cliffTerent attempts which have been made 
in this direction, both by myself and others, the object aimed at has been to 
set up a chemical action that can be regulated and controlled, so that while 
nitrous ether is produced in sufficient quantity there shall not be an undue for¬ 
mation of secondary products or an excessive destruction and waste of alcohol 
and nitric acid, as frequently occurs in the ordinary processes. 
It has been proposed to effect the required object, (1) by adding the nitric 
acid to the spirit in successive quantities as the process proceeds j or (2) by 
altering the strength of the acid; or (3) by interposing an inert medium be¬ 
tween the acid and alcohol, through which they shall mutually pass by diffu¬ 
sion ; or (4) by causing the nitric acid to be graduall}^ produced in the retort 
by the decomposition of a nitrate ; or (5) by substituting a nitrite for a nitrate ; 
or (6) by substituting nitrous acid for nitric acid in the free state; or (7) by 
using some ingredient which, in the presence of the spirit, will convert the 
nitric into nitrous acid, without involving the destruction of alcohol and con¬ 
sequent formation of aldehyd and other secondary products. 
The processes of the Edinburgh and Dublin Pharmacopoeias belong to 
methods (1) and (2); they can only be practically applied on the small scale, 
and they are not economical. The process referred to under (3) is that of Dr. 
Black, which Berzelius preferred to all the others; but this, again, is not a 
manufacturer’s process, and cannot be made such. It consists in putting 
into a long narrow cylindrical vessel, 9 parts of rectified spirit, then intro¬ 
ducing beneath this, by means of a funnel-tube reaching to the bottom of the 
vessel, 4 parts of water, so that it shall form a distinct stratum beneath the 
spirit, and afterwards introducing in the same way, beneath the water, 8 parts 
of strong nitric acid. These are allowed to stand undisturbed, for two or 
three days, m a room at a uniform temperature, not exceeding 53°. At the 
