38 Mr Whytock mi tlui applicatioii of Oars to Steam-Boats. 
ciples which, I conceive, have been overlooked. And I am 
convinced that the whole apparatus might be made more simple 
than that which is now in use. 
The advantages which would attend the use of oars would 
be, that they could be singly replaced, even without stopping 
the machinery. They could be elevated into a perpendicular 
position, when it was intended to stop the vessel for a short 
time, and the engine still be allowed to play. And when necessa- 
ry to pass close to another vessel, the same manoeuvre could be 
practised. And, finally, when a certain degree of impetus had 
been given to the vessel, such an apparatus would not act in the 
way of counteracting this, the bottom of the vessel being left 
perfectly clear of all incumbrance. I have no hesitation in say- 
ing, that were this plan adopted, there would be a most material 
saving of power, and the velocity with which the vessel would 
plough the waves, would exceed, in an inconceivable degree, the 
greatest feats of the kind yet performed. 
Fig. 8. Plate I. represents the balanced oar ; A is a section of 
the side of the vessel ; B the end of the oar to which the power 
would be applied ; C the pivot upon which the oar would turn ; 
D the joint of the oar ; E the lever by which the oar would be 
elevated, and its weight adjusted ; F the pulley over which the 
cord would pass, and G the weight by which the oar would be 
balanced. Instead of a weight, a strong spring might be em- 
ployed, such as is shewn at PI. 
Along with the drawings which accompany this article, I have 
given a sketch of a screw, (See Fig. 4. Plate I.), which I con- 
structed five or six years ago, with a view to a trial of its efficacy 
in propelling a vessel. Although I was prevented at that time 
from completing the experiment, enough was ascertained to 
warrant a trial upon a more expensive scale, as soon as time 
and opportunity should permit. The following is the way in 
which the screws that I used were constructed. 
A cylinder of wood feet long, and inches thick, 
was divided by means of a cord in a spiral direction. The 
cord made turns in the length of the pole. The sole 
use of this cord was to show the direction of the spiral line, 
until it was marked out and pierced with a succession of 
holes, at distances of about two inches between each. Into 
