Steam Engine. 
It will after all, be proper to distinguish carefully be- 
tween the quantity of power expended, and that portion 
of it which is usefully employed : but a due considera- 
tion of this would too widely extend the limits of the 
present communication. Indeed I ought to apologize to 
yourself, and the scientific part of your readers, for dwell- 
ing so long as I have done upon topics which ^re well 
known to all who are conversant in the theory of mecha- 
nics : but if those, for whose use this letter is chiefly in- 
tended, shall derive some precise information, or add to 
the stock of their practical knowledge, by any hints of 
mine, I shall not fear being heavily censured for having 
entered thus into minutiae. 
I am. Sir, 
Your’s very respectfully, 
OLINTHUS GREGORY. 
Royal Mil. Academy, Woolwich, 
June lO^A, 1805. 
(11 Nicholson* s Journal^ p. 145. | 
On the Construction of the Beams of Steam Engines. By 
Mr, J. C. Horn BLOWER, From the Author, 
Dear Sir, 
I BEG leave through the means of your Journal, to lay 
before the public an account of the framed lever mention- 
ed at the close of the article Carpentry in the supplement 
to the Enclycopedia Britannica, as it was originally de- 
signed for an engine to have been erected at Amsterdam 
in the year 1776, together with two others, possessing 
every possible advantage of levers consisting of small 
scantles. 
I know not by what means the lever above referred to 
come to be constructed with the disadvantages intimated 
by the writer of that article, but there is no necessity for a 
hole to be bored, or a bolt to be driven in any part of the 
framing between the arches, except for the chain stays. 
I 
ill 
