10 
ON SPIRIT OP NITROUS ETHER AND NITRITE OF SODA. 
40 fl. oz. of rectified spirit. Distil 35 fl. oz. (seven times the quantity of 
the nitrite employed). Specific gravity *843. The preparation of the nitrite 
of soda was made a separate process, thus,—16 oz. nitrate of soda, 1 \ oz. of 
charcoal recently, burned, and in fine powder : mix, and drop the mixture 
in successive portions into a clay crucible heated to dull redness. Raise the heat 
to liquefy.it, and pour on to a clean flagstone. In carrying this operation 
into practice, it was found that 32 fl. oz. only could be obtained by distillation, 
and that it required the addition of more spirit to make up the yield to 35. 
The specific gravity, also, was *850, and the percentage of nitrous ether below 
that indicated. In examining into the reason of this deficiency, it was found 
that on the addition of the mixed spirit and acid to the salt, a crust of sulphate 
of soda, in a comparatively insoluble state, was formed on the surface of the ni¬ 
trite of soda, which .enclosed and thus protected the remainder from the action 
of the acid, until a great deal of the spirit had distilled over, and that it was 
hence some time before much nitrous ether was produced. To prevent this 
the nitrite was first dissolved in 10 fl. oz. of water before the addition of the acid 
and spirit, and with this modification the whole quantity directed can readily 
be distilled off. J J 
A great deal of difficulty, I believe, has arisen in preparing the nitrite of 
soda ±or this manufacture, and there can be no doubt that if great care is not 
observed in the process of deflagrating the nitrate of soda and charcoal, a con¬ 
siderable percentage of carbonate of soda or even caustic soda is formed, with, 
of course, an equivalent loss of nitrite. The proportion of charcoal ordered is 
indeed rather above the quantity required, 1T3 oz. being the calculated propor¬ 
tion instead of T25. One ounce, however, will be found practically sufficient. 
In working on the large scale, the process of deflagration is also a very tedious 
one, and if the workman endeavours to expedite his operations by the projection 
of too large a quantity of material at once into the heated vessel, the chemical 
action, is increased to such an extent that he is sure to destroy a great deal of 
the nitrite.he is endeavouring to prepare. As I had obtained such good results 
by controlling this operation within, its lowest possible limits, it was attempted 
next to effect the partial deoxidation of the nitrate of soda without allowing 
deflagration to take place at all, and this at times has been very successfully per- 
foimed ; but it has this great drawback, that despite all the caution employed, 
the mixture is always liable to burst suddenly into deflagration and even compa¬ 
rative explosion. 
It "was next tried to substitute a harder form of carbon for the purpose, and 
finely powdered plumbago was selected; this is somewhat more manageable 
and under control, and has answered the purpose better. Several hundred 
pounds weight of salt, containing about 75 per cent, of nitrite of soda, have 
been manufactured by this means ; still at times we have had sudden bursts of 
deflagration, and this makes the men nervous, from its occurring when they were 
off their guard, and burning their clothes or skin. 
My next experiment was to substitute for the charcoal an equivalent amount of 
carbon in the form of starch, and this has yielded us the most satisfactory results, 
and with very little trouble. Seven parts of dried nitrate of soda in fine powder 
is mixed with one of starch powder, and thrown by small quantities at a time 
into a shallow iron pan heated from below ; the mixture spumes and melts as 
the water and carbonic, acid pass off, and the salt ultimately fuses. When it has 
become quite white, it is laded out and cooled. We have already made between 
three and four hundred pounds weight by this process, and without any annoy¬ 
ance from deflagration, the heat of course being carefully regulated. In these 
operations we have always employed iron vessels, as the metal vessel relieves us 
from the annoyance of loss arising from leakage or fracture of the earthen 
crucible and the small quantity of oxide of iron that is found mixed with the 
