PHARMACY AT THE DUBLIN EXHIBITION. 
00 
nected with tlic distillation of wood. They include acetic acid and acetates , 
pyroxylic spirit, pear essence (acetate of amyloxide), and pineapple and raspberry 
essences. It is to be regretted that Mr. Eschwege should not have shown here 
his purified wood spirit, which at the time of the London Exhibition of 1862 
first attracted attention. The specimens there exhibited could not be said to 
illustrate a manufacture of any importance; they rather proved that wood 
spirit was really a fluid possessing of itself no marked taste or odour, and that 
both were due to the presence in the commercial article of oily hydrocarbons 
which could be separated by a peculiarly modified process of filtration through 
charcoal. Mr. Eschwege now conducts the purification of wood spirit on a very 
large scale, and can supply it in unlimited quantity. The specimens which I 
have lately examined are very much purer than that to which I drew attention 
in 1862. 
The probability of this purified pyroxylic spirit being used as an adulterant of 
wine-alcohol is now so seriously apprehended by the excise authorities, that as 
the readers of the Journal know, a check is to be put upon its manufacture in 
the shape of a restrictive duty. Two years ago, the suggestion that it could be 
so employed was treated at the Somerset House laboratory with quiet contempt. 
The presence of the “ fruit essences” mentioned in the case of Messrs. Hirst 
and Company, reminds me that this manufacture, which may be said to have 
originated with the Exhibition of 1851, has, although it has attained consider¬ 
able importance, not been enriched by any new organic compounds for a long 
time. Although nearly every fruit is now represented by an artificial essence, 
which more or less resembles its proper flavour, these are, for the most part, 
simply mixtures formed from two or more of a very small series of compound 
ethers, either with or without the addition of essential oils. 
At the time of the 1862 Exhibition, Hr. Hofmann called attention to suberic 
ether , which has been pointed out by Mr. H. B. Condy to closely resemble in 
odour the mulberry. No new bodies of this class appear—at least not in the 
British department—in the Exhibition. 
Messrs. Johnson and Matthey, whose names have become as closely associated 
with platinum as that of Mr. Sonstadt with magnesium, or that of the 
Messrs. Bell with aluminium, contribute an array of specimens of unrivalled ex¬ 
cellence and beauty. This case is indeed the great attraction of the scientific 
part of the Exhibition, and as its proprietors have, with commendable fore¬ 
thought for the public convenience, placed within easy reach a very concise 
description of its contents, the latter have been honoured with more notices 
—newspaper and otherwise—than perhaps any other collection of manufactured 
products in the Exhibition. Passing over the platinum apparatus, which is, of 
course, chiefly that employed in the sulphuric acid manufacture, and an ad¬ 
mirable show of analytical desiderata —among which a crucible of luscious gold 
is particularly beautiful—and might almost excusably be coveted by a chemist 
I may dwell for a moment on the illustrations of the newly-born magnesium 
industry. These, Messrs. Johnson and Matthey show, as agents for the “ Mag¬ 
nesium Metal Company.” First, there is a mass of the pure metal, # weighing 
134 ounces; then a solid magnesium casting—an obelisk 162 ounces in weight. 
The latter and a steam valve (why, by the way, choose to make a steani valve 
of so oxidizable a metal?) well demonstrate the ease with which magnesium is 
cast and how well it adapts itself to the intricacies oi the mould. Its low spe¬ 
cific gravity and the process by which—though not ductile—it is pressed into 
wire, are simultaneously illustrated by a coil of wire rather more than a mile 
long, which does not quite weigh three pounds, and by another of ribbon which 
weighs but two and a half pounds, and measures 4800 feet. Both wire and 
ribbon are, of course, only used for the production of the u magnesium light. 
It has, by the way, been lately pointed out that a compound strand, consisting 
