239 
Intelligence, 8£c. 
ing is not to be viewed with the eye of fastidious criticism ; al- 
though in itself it is by no means an indifferent performance, yet 
its merit arises from its singularity. Probably, not one hundred 
persons in the United States have ever had an opportunity of see- 
ing a similar production. The great difficulty of passing the glass 
through the press of the copper-plate printer, without breaking it, 
which, in common with others, the Editor has experienced, has al- 
ways prevented this species of engraving from being extended be- 
yond the etching itself. The only plate which is known to the 
Editor as successfully accomplished, is a frontispiece to the Sd 
London edition of Parke’s Chemical Catechism. It is scarcely 
more than a bare outline of some of the apparatus of chemical sci- 
ence ; and, although so rudely executed, as to bear no comparison 
with the present, yet Mr. Parke says of it, « I have reason to be- 
lieve it exhibits a more favourable specimen of printing from 
glass, etched by fluoric acid, than any that has hitherto been pro- 
duced.” (p. 233.) 
The Editor is much indebted to the assistance of Mr. Tiebout 
whose excellence as an engraver is well known ; but he is more 
especially so to the patience and perseverance of Mr. Duffy, (cop- 
per-plate printer, with Mr. Dainty, of this city,) by whose co-ope- 
ration the plate has been so successfully printed., The difficulty 
may be appreciated, when it is stated, that after seven hundred 
plates had been taken off, the glass was unfortunately broken, and 
the design of giving it to the public was nearly suspended. The 
uncommon patronage however which the Emporium has already 
received, called for every exertion on the part of the Editor ; and 
he accordingly executed another etching from the former, from 
which the remaining plates have been taken ; and in a way, which 
experience leads him to hope, will facilitate any future attempts of 
this nature. 
Intelligence and Miscellaneous Articles ,* including .. Memoranda , 
Hints , Precepts , and Recipes , for the use of Artists , Manufac- 
turers , and others. 
Mr. Carnot in his new treatise on the defence of fortified places, 
recommends the besieged to fire howitzers wadded with grape 
shot or musket ball, at an elevation of 45 degrees, when the enemy 
have made their approaches to within a certain distance, which may 
be effected without their being exposed, and the shot will do more 
execution, not being stopped by the enemy’s works. Mr. Carnot’s 
suggestion has been adopted in France, and now forms part of the 
artillery exercise* Tilloch , No. 1 59 , 
