1819.] Description of Stevenson’s Dalswinton Steam-Boat. 283 
sents a plan of the hold of the double vessel with the water- 
course between them. The plan No. 2, shows the accommoda- 
tion upon deck, consisting of a fore and after cabin, with 
cooking-house, &c. &c. The section No. 3, represents a. 
longitudinal section of the vessel in the direction of the keel 
from stem to stern, showing one of the lower holds in which a 
steam-engine and boiler are fitted up. Over this again are the 
cabins, with a walk and railing upon the top. Between the 
hold and the cabins, a space is marked off with strong plate-iron 
_ for ventilation, in which a current of air is kept up from stem 
to stern. Lastly, the cross sections marked A B and C D refer 
to the corresponding letters on the plans, and exhibit a trans- 
verse section, or view of the boat, both above and below the 
water line. This general plan on which the several parts are 
marked, it is presumed will easily be understood, by those espe- 
cially who have had any experience of the steam-boat, without 
the necessity of multiplying technical references, which are 
always irksome to the general reader. 
This plan of a steam-boat, in so far as comfort and accommo- 
dation to passengers, or the conveyance of goods, are concerned, 
it is humbly conceived will be found to be extremely useful, and 
deserving the attention of the public ; and especially of those 
whose concerns more immediately lead them to have an interest 
in the improvement of the steam-boat. 
A question will naturally occur to the practical seaman with 
regard to the strength of such a vessel ; while the philosophical 
observer may wish to be satisfied as to the fitness of this distri- 
bution of the wheels for the purposes of speed or velocity. With 
regard to the strength of such vessel, every one will be satisfied 
that while afloat she must be perfectly secure, as the water 
presses upon all sides equally, and must give her great stability. 
In order also to enable such a vessel to take the groundina d 
harbour, it will be observed from the cross sections marked A B 
that considerable facility is obtained in framing this double 
vessel in a strong and substantial manner, particularly at the 
space between the two water wheels. 
On the subject of the velocity of a boat of this construction, 
the most satisfactory trial is no doubt obtained from expe- 
riments upon the great scale. Regarding the full and proper 
operation of the two wheels, situated as here proposed, there 
seems to be no reason for doubting. In the example here 
offered, the water-course is delineated upon a narrower scale 
than choice would have dictated; but this boat, being in- 
' tended to suit the lockage of the Forth and Clyde canal, which 
will not admit vessels of a greater breadth than 20 feet and more 
than 70 feet in length, the breadth of beam is necessarily con- 
fined more than would otherwise have been requisite for the 
ordinary purposes of navigation, or birthage, even in a circum- 
