1810.] Mechanical Illustration of the Catenary Curve. 
one was either projected, or perhaps ex- 
ecuted, in the vast town of Adrianople, 
as a central edifice for all those fixed in 
the environs of that country. 
For the execution of this vast project, 
independently of the disciplined troops 
in barracks at Constantinople, there 
were more than 12,000 effective men, in 
the above towns of Natolia; and had the 
design continued, there was no doubt 
that there might be obtained with the 
greatest facility, disciplined troops be- 
yond even the exigency of the case. 
Besides that, the corps of artillery, gre- 
nadiers, and miners, were complete, and 
perfectly disciplined. The marine was 
placed in a similar state of improve- 
ment. Levendtziftihk and  Scutari 
were to be the two cardinal points, one 
for Romelia, the other for Asia; from 
which depots they could draw enlightened 
officers, to train and exercise the new 
recruits in the respective establishments. 
[Such were the wise projects of the un- 
fortunate Selim: and deeply is it to be re- 
gretted, that innovations, however excel- 
Jent, cannot with safety be executed ra- 
pidiy, until the public mind is fully pres 
pared to receive them. ‘Those ruffians, 
the Janissaries, however, undoubtedly 
éaw the future extinction of their power, 
in regulations imperiously demanded by 
the totteringstate of the Ottoman empire. ] 
a 
To the Editor of the Monthly Magazine. 
SIR, 
AVING observed in your Maga- 
zine for September, 1809, a 
concise account of the methods of de- 
scribing geometrically the celebrated 
curve called the catenary, allow me to 
propose the insertion of the following 
A. Cc 
5B 
325 
elegant mechanical illustration of that 
line, taken from the works* of John 
Bernouilli: I believe it has never yet 
appeared in any English publication, 
Let AE be a lever indefinitely long, 
P a weight suspended from the point A, 
C A equal toC B; and BF Ga catenary 
whose vertex is B, axis BE, and cene 
tre C, 
If from any point D of the part of the 
lever BE, a weight Q equal to the 
weight P be hung, so that its direction 
may be in the tangent (2,8) tothe point 
F of the curve, where a line at right ane 
gles to the axis let fail from D would cat 
it: the weight Q in this situation will 
counterbalance the weicht P. 
I cannot help remarking, that it 
would have been more satisfactory, if the 
commentator on the letter of Lapicida 
(Monthly Mag. Nov. 1809) had, instead 
of indulging a flippancy of wit, shewn 
some marks of that * reputation which 
he says he has acquired in his college,” 
in confuting the clear and positive opi~ 
nion given by Dr. Robison of the fale 
lacy of the Emerson theory of arches, 
confirmed as that opinion was by numee 
rous experiments, and repeated observas 
tion, (Art, Arch, Ency. Brit. Sup. 3d 
edit.) 
An OBSERVER. 
* Johannis Bernouilli Opera omnia, vol. 1, 
page 61, and vol. 3, page 504, edit. Lan. 
and Gen. 
+ This may be done by making the thread 
DHQ, pass round a pulley at H directly 
above F. : 
2 
LD 
