APPARATUS FOR MAKING DILUTED NITRO-HYDROCHLORIC ACID. 421 
It has turned brown at the surface where it comes in contact with the vessel in 
which it was heated. My experience is, that the process in the Pharmacopoeia, 
if it be strictly adhered to, together with ordinary precautions such as I have 
mentioned, is, after all, the best one, and all that could be wished for. 
To any chemist whose consumption of this syrup is very irregular, and who 
may have to keep it for a longtime, I would suggest another method of bottling 
off, viz. : Make the syrup and the solution ; weigh them separately, and to the 
former add the quantity of boiled distilled water necessary to make up the 
weight of the whole. Mix this well with the simple syrup, and half fill a 
number of weighed bottles of any desired size. Then, having measured the 
solution of the iodide, divide it off, and pour the required quantity into each 
bottle by means of a long funnel reaching to the bottom, and finally make up 
the weight of each with the simple syrup. The advantage of this method is, 
that the solution is in a distinct layer at the bottom, which, being protected by 
the syrup above, will remain without change, for aught I know, for years. 
When the syrup is wanted, you have simply to well mix the solution by shaking 
the bottle, and you will have it as when first made. This method is very simple, 
and, by a little calculation, easily managed. Finally, when the syrup in 
the opened bottle has become coloured, I have always found, and without 
failure, that by exposing it to the direct rays of the sun for a few hours it will 
return to, or rather become lighter than, its original colour. In winter time, 
however, the sun is not sufficiently powerful. But the syrup may be kept until 
summer, for, when it gets even quite brown, a day’s summer sun will bring it 
right. Thinking that specimens might be interesting, I have reserved a bottle 
each time I have had to make the syrup, and marked the date thereon. The 
specimens are made by both of the above processes, and to all appearance are 
ver y good. r Ihey will be on the table for inspection at the pharmaceutical 
meeting for January. 
AN APPARATUS FOR MAKING DILUTED NITRO-HYDRO¬ 
CHLORIC ACID. 
BY J. T. PORTER. 
Having for some time noticed great variation in the strength of samples of 
diluted nitro-hydrochloric acid made according to the directions of the British 
Pharmacopoeia, I was induced to make some experiments on the subject, 
feeling confident that some apparatus could be devised which would obviate 
the difficulty. To obtain this result, in the first instance I put the acid into 
a bottle sufficiently large to hold the whole when diluted, tied down the 
stopper, and after twenty-four hours diluted it: yet much gas was lost, and 
the experiment was accompanied with considerable danger, for on one occasion 
the Winchester quart burst, owing to the pressure of gas within it. This 
failure, however, gave rise to another experiment, viz. to have the mixed 
acid contained in one bottle, and the water necessary for subsequent dilution 
in another, and to connect the two by a glass tube ; the idea being that, as 
the gases were generated, they would become absorbed by the water, and 
after twenty-four hours had elapsed, the acid might be diluted without discon¬ 
necting the apparatus. This apparatus answered very well in that it did 
not allow the gases to escape, but it was somewhat complicated in form as 
well as difficult to fix, since cork could not be used. 
Having to make the acid in large quantities, I thus had an opportunity of 
improving the above contrivances. At length an apparatus was constructed 
