ON THE PllEPAKATION OF SPIPtlT OF NITROUS ETHER. 
509 
As the chemical action becomes more intense it assumes a more complex cha¬ 
racter, large quantities of uncondensable vapours are given off, and much waste 
of spirit and of acid necessarily ensues. 
The following experiments were made to determine the limits in the ratio of 
acid and spirit, within which mixtures of nitric acid (sp. gr. 1-42) and rec¬ 
tified spirit, when submitted to distillation in the usual way, yield nitrous 
ether suitable for use in medicine :— 
1. A mixture of 1 fluid oun-ce of nitric acid and 3 fluid ounces of spirit was 
put into a retort, furnished with a thermometer, and to which an efficient con¬ 
denser was attached. The heat of a lamp was applied until the temperature 
rose to 185°, when, chemical action having commenced, the lamp was extin¬ 
guished and the process allowed to proceed spontaneously. The temperature 
of the liquid quickly rose to 205°; a violent reaction occurred, and much of 
the vapour which passed over escaped in the uncondensed state. After a short 
time the temperature fell to 175°, but again rose spontaneously to 190°. AVhen 
the action finally subsided, there were two fluid ounces of condensed liquid 
in the receiver, and nine fluid drachms of a strongly acid liquor left in the 
retort. 
2. A mixture of 1 fluid ounce of nitric acid and 4 fluid ounces of spirit was 
submitted to distillation with an arrangement such as was adopted in the previous 
experiment. A little pure spirit came over in the early part of the experiment, 
but this was soon followed by the production of ether, which commenced when 
the temperature had reached 195°. The action was not so intense as in the 
previous experiment, and therefore the heat of the lamp was not withdrawn, 
but the flame was lowered. The temperature of the liquid in the retort rose to 
200°, but afterwards fell to 185°, without any alteration in the source of heat; 
at this temperature ether came over freely, but without altering the flame of the 
lamp the heat of the liquid in the retort rose to 195° before the action ceased. 
The distilled product amounted to two and a half fluid ounces, and the residue 
in the retort to seven fluid drachms. 
3. A mixture of 1 fluid ounce of nitric acid and 5 fluid ounces of spirit was 
submitted to distillation as in the previous experiments. When the tempera¬ 
ture had risen to 185°, spirit began to pass over without any ether. The tem¬ 
perature gradually increased to 205°, with irregular ebullition, but still nothing 
but spirit passed over. The irregularity of the ebullition caused the tempera¬ 
ture to vary between 200° and 205°, and this continued until six fluid drachms 
of spirit had distilled, when chemical action commenced, and ether began to ap¬ 
pear in the distilled product. The temperature now rose to 208°, and the 
action became so violent that much of the vapour escaped uncondensed. As the 
process proceeded, however, the temperature fell, and the action then became 
more regular and satisfactory. The result was that the total distilled product 
amounted to three and a half fluid ounces, while seven fluid drachms of liquid 
were left in the retort. 
These experiments show that when a mixture of nitric acid and spirit is sub¬ 
mitted to distillation, as it usually is in the preparation of sweet spirit of nitre, 
the proportion of spirit greatly exceeding that at which chemical action occurs 
and ether is produced, the first part of the process consists in the simple distil¬ 
lation of alcohol; and when this has been carried so far that the spirit which 
remains in the retort is about four times the volume of the acid, ether begins to 
be formed. The exact proportion of acid and spirit required for the production 
of ether depends upon the temperature at which they are brought into contact 
with each other, as will be seen from a comparison of experiments 2 and 3- The 
higher the temperature to which the mixture is subjected, the larger is the pro¬ 
portion of spirit that may be present when the ether-producing action occurs; 
but if the temperature be above 200°, the action is liable to become so violent 
