Ilktory of MechankaJ ^ 
It will be observed, that no advantage is. taken of the expan^^ 
sive force of the explosion, except to drive away the common air; 
from the lower part of the cylinder. The construction of such 
machines admits of endless modifications ; but the expenc,e of the 
hydrogen gas appears to be a prohibition to its employment, ex- 
cept in some rare situations. 
2. Account of Mr BaWs Steam Passage-Boat for the AUoa> 
Ferry. ’ 
We have much pleasure in laying before our readers the fok 
lowing account of a very excellent Steam Passage-Boat, which has 
been proposed by Mr Bald, for facilitating the transit of passen-^ 
gers, cattle and carriages, over the river Forth, at Alloa Ferry 
The plan displays much Ingenuity and knowledge, and will, we 
d.oubt not, be followed at many other ferries. 
“ The passage-boat is represented in Plate V. Figs. % and 3.^ 
where, 
A.B.C.D. 
E.F.G.H. 
I.K.L.M. 
N. 
O. 
P. P. 
Q. Q. 
B. 
S. 
T. 
U. 
Are areas where cattle stand. 
Areas connecting the wings where carriages stand, 
with horses attached. 
Poops for helmsman, and cabin for passengers. - 
Paddles. 
Cylinder pf steam-engine. > 
Chimneys. 
Boilers. 
Coal-house. 
Festoon chains to hook and unhook similar chainsj 
i and keep the cattle within the platforms 
A.B.C.D. 
The wings. . , . ; 
Folding guard boards. 
The extreme length of the boat upon deck to be about 82 feet. 
Breadth over all upon deck, - - 20 feet. 
Additional for two wings five feet each, - 10 
Breadth over wings, - - - — SO 
* Mr Rennie estimated the expence of a bridge at L. 60,000. The breadth of 
the river is 570 yards. 
