December 10, 1870.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
463 
the Society in London. He found among the large 
body of pharmacists in the United States many indi¬ 
viduals eminent for varied experience, practical 
skill and ripened intelligence, whose matured powers, 
at present confined to the routine of their own stores, 
might, under kindly and more public circumstances, 
nobly contribute to the service and progress of the 
profession of pharmacy. 
SP. iETHERIS NITROSI, B.P.* 
BY ALFRED E. TANNER. 
The process in the B. P. is the one usually known 
as Redwood’s; it consists in distilling a mixture of 
rectified spirit, nitric and sulphuric acids, together 
with copper wire, at a certain temperature, in a 
glass retort, furnished with a thermometer; and in 
operating on the Pharmacopceial quantity, 15 fluid 
ounces are ordered to be drawn over, and this dis¬ 
tillate is to be mixed with 40 fluid ounces of rec¬ 
tified spirit, or a sufficiency, so that the mixture may 
correspond to the tests for sp. gr. and percentage 
of C 2 H 5 N0 2 , this latter being determined by means 
of a saturated solution of Ca Cl. 
Now I have followed this process for the prepara¬ 
tion of spiritus setlieris nitrosi ever since the Pharma¬ 
copoeia was published, but have never succeeded in 
collecting the amount of distillate there ordered ; on 
no occasion have I been able to produce more than 
about 11 fluid ounces, excepting by the addition of 
more nitric acid than the Pharmacopoeia allows, 
and then the product has been too rich in nitrous 
ether. 
I have usually found this 11 fluid ounces of distillate 
to contain 50 per cent, of C 2 H 5 N0 2 ; that is, it will 
show a separation of 42 per cent, when agitated in a 
graduated tube with double its volume of saturated 
solution of CaCl; this, then, appears to contain the 
whole amount of C 2 H 3 N0 2 required, viz. about 5£ 
fluid ounces, or 3G'0 per cent, of the quantity ordered 
by the Pharmacopoeia to be drawn over, and on mix¬ 
ing this with four times its volume of rectified spirit, 
the mixture corresponds exactly with the spiritus 
aetlieris nitrosi of the Pharmacopoeia, showing 10 per 
cent, of C 2 H 5 N0 2 by the CaCl test, and having a 
sp. gr. -84(5. 
I should mention that this 11 fluid ounces of dis¬ 
tillate was produced within the limit of temperature 
ordered, viz. 180°, but bv increasing the heat to 200° 
there was no difficulty in distilling about 4^ fluid 
ounces more, but that appeared to consist princi¬ 
pally of spirit; it was not acid when first distilled, 
but became so in a few days. On the last occasion 
of preparing sp. ietlier. nitros., I made a few notes 
which may, perhaps, be interesting to some. 
The quantities operated upon were those mentioned 
in the B. P., viz. sp. vini rect. Oj, acid nitric 3 fluid 
ounces, acid sulphuric 2 fluid ounces, and copper wire. 
These ingredients (with the exception of ^ fluid ounce 
of the nitric acid which was set aside to be added 
subsequently), were put into a glass retort, and the 
mixture distilled at a temperature commencing at 
100° and rising to 175°. The nitrous ether began to 
form at 100°, which is 10 degrees lower than the 
point indicated in the Pharmacopoeia : when the tem¬ 
perature had risen to 175° and about 8 fluid ounces 
. * Read at a Meeting of the Liverpool Chemists* Associa¬ 
tion, Nov. 27, 1870. 
had passed over, the boiling ceased, and no more could 
be distilled without exceeding the limit of tempera¬ 
ture, viz. 180°; so the contents of the retort were 
allowed to cool somewhat, and the remaining \ fluid 
ounce ot nitric acid was added; the distillation was 
then continued as before and 3 fluid ounces more 
passed oyer, making together 11 fluid ounces; a 
fresh receiver was adapted to the apparatus and the 
contents of the retort heated to 200°; the distillate 
thus produced measured 41 fluid ounces, and con¬ 
sisted chiefly of spirit; it was nearly neutral to test 
paper, and had veiy little flavour of nitrous ether, 
its sp. gr. was ’807. I further distilled the contents 
of the retort until a temperature of 220° was shown ; 
this produced about 2 fluid ounces more of a liquid, 
chiefly spirit and water, having a sp. gr. '897, this 
was also neutral, but had a disagreeable odour. The 
11 fluid ounces of distillate above referred to was 
then examined and found to have a sp. gr. ’881, and 
showed by the CaCl test a separation of 42'5 per 
cent., thus corresponding to 50‘5 per cent. C 2 H 5 N0 2 . 
This agrees tolerably well with the calculated sp. gr. 
of a mixture of equal parts of rectified spirit ( 838) 
and nitrous ether (’900), which gives ‘870 as a mean; 
the difference between these numbers may, I think, 
be accounted for by the condensation which takes 
place on mixing. 
These considerations, I think, show that there is 
more spirit used in the first part of the process than 
is necessary, or what amounts to the same thing, 
too little nitric acid. I think a proportionate increase 
of nitric acid should be used, and the distillate tested 
as to the amount of C 2 H 5 N0 2 it contains, and if, as 
in the case just mentioned, it is found to contain 50 
per cent., then 1 volume mixed with 4 volumes of 
rectified spirit would furnish spiritus setlieris nitrosi 
of the Pharmacopoeia strength. 
On the question of keeping this compound I re¬ 
gret having no suggestion to offer. It seems inhe¬ 
rent in the nature of nitrous ether, even when pure, 
to change rapidly, becoming strongly acid after be¬ 
ing kept a few days. Doubtless the keeping pro¬ 
perties of sp. nitr. are in direct proportion to its 
strength in ether. A 5 per cent, solution is, I think, 
more desirable than the present strength, and it 
would approach nearer to that usually sent out by the 
wholesale houses. I have reason to believe it is 
never sent out of the strength ordered in the B. P. 
The only possible remedy to prevent this decom¬ 
position that I can conceive may be the introduction 
of some other substance which will exert a preserva¬ 
tive influence over it. I have not made any experi¬ 
ments in this direction, but they are well worthy our 
attention. Some organic substance, such as C H Cl 3 , 
might possibly be of use. I see acetic ether recom¬ 
mended in one of the American journals of phar¬ 
macy, but can say nothing of it from experience. 
Before concluding, I should like to say a word or 
two of a practice which I consider highly repre¬ 
hensible. Most of the wholesale houses, I believe, 
send out what they term solutio retlieris nitrosi 1 to 
7 for the purpose of making sp. (ether, nit., and 
doubtless the confiding pharmacist considers he has 
got hold of a most convenient article for making this 
otherwise uncertain preparation. I have even heard 
of its being used in the proportion of 5j for every 
3j of spiritus (etheris nitrosi ordered, and trusting to 
the other tinctures ordered in the mixture to make 
the requisite amount of spirit. I had occasion the 
other day to examine a sample of this preparation 
