SALE OE ALCOHOL FOR MEDICAL AND CHEMICAL PURPOSES. 467 
crystallization of the citric acid out of the solutions, as to cause a most destructive action 
upon that remaining in the mother-liquors. Various means have been used to prevent 
this, the most successful being, doubtless, the substitution of water for steam heat 
during evaporation ; but as the lower temperature requires longer exposure to heat, the 
advantage thus gained is almost counteracted. 
The most effectual means of remedying this is by passing the mother-liquors, so soon 
as they are found to contain any dangerous amount of sulphuric acid, through a fresh 
portion of citrate of lime, which not only removes at once all free sulphuric acid con¬ 
tained, but there is also deposited a quantity of flocculent matter which was held in 
solution by it, and which is no doubt the cause of the mother-liquors when old crystal¬ 
lizing only with such difficulty. The flocculent precipitate referred to consists for the 
most part of sulphate of lime, but contains also some phosphate of iron and alumina, 
and accumulates more or less according to the care bestowed in evaporating the solution, 
it being most insoluble when the liquor contains about 6 lb. of citric acid to the gallon, 
marking 1200 to 1250 (according to temperature) on the hydrometer, and if not sepa¬ 
rated from the solutions at that point it partly dissolves again as they become more con¬ 
centrated. 
As a consequence of this, it is found necessary, in the usual working, to re-saturate 
these solutions so soon as they become surcharged with these matters and the sulphuric 
acid above referred to, and thus renew the whole process continually, which ol course 
necessarily increase greatly the expense of working, as well as loss both in time and 
material; but when the process of purifying referred to is adopted, it is found practicable 
to work continuously with the same liquors without saturating (of course depending 
upon the amount of carefulness in the manipulation), and in such case the cost of pro¬ 
duction is lessened nearly one-half. The crystals of citric acid also being most tenacious 
of sulphate of lime will often hold it so as to render them contaminated even to the 
second or third crystallization, producing an opacity which when dried gives them an 
appearance of efflorescence ; materially affecting their commercial value. 
This difficulty, which is also, in the opinion of the writer, to be overcome, will form 
part of a future paper.— Chemical News. 
SALE OF ALCOHOL FOE MEDICAL AND CHEMICAL PURPOSES. 
A question of importance to photographic and other chemists has just been decided. 
It seems that an excise officer bought some strong alcohol of Messrs. Horne and Thorn- 
thwaite, and then laid an information against the firm. Messrs. Horne and Thorn- 
thwaite thereupon wrote to the Commissioners of Inland Revenue, stating that in 1856, 
when supplying the photographic outfit to the Royal Engineers, they had, through the 
late Captain Fowke, inquired of the Board whether they were allowed to sell alcohol for 
photographic or scientific uses, and the reply given was to the effect that no notice 
would be taken of such sale. Messrs. Horne and Thornthwaite also urged that the 
spirit supplied by ordinary dealers was useless for scientific purposes. I hey stated, 
further, that they were of opinion that they were fully justified in selling an alcohol the 
strength of which is so high that it cannot be tested by Sikes’s hydrometer, as such an 
article could not have been contemplated by the Act, which directs all spirits to be 
tested by Sikes’s hydrometer ; and they concluded by appealing to the Commissioners, 
on their own behalf and the many other establishments interested, to decide what they 
might legally sell. The reply of the Commissioners will be found below. We may add 
that Messrs. Home and Thornthwaite have been advised not to sell alcohol under 60 
over proof, and in quantities of not more than one gallon at a time. 
“ Inland Revenue , Somerset House , London , W.C. 
“30 th January , 1866. 
« Gentlemen,—The Board of Inland Revenue having had before them your application 
of the 17th instant, I am directed to state that the law absolutely prohibits the sale of 
any spirit without licence, but that this department is not in the habit of interfering 
with chemists who sell small quantities of highly rectified spirits, such as cannot be 
procured from ordinary spirit-dealers, for medical or scientific purposes only. 
“ I am, Gentlemen, your obedient servant, 
“Adam Young, Assistant-Secretary. 
“ Messrs. Horne and Thornthwaite .” 
