

TRANSACTIONS OF THE SECTIONS. 33 
the consideration of draft of water was rejected or overlooked, and a finer midship 
section taken, although with a larger draft of water. In one case also the rudders 
were considered as part of the length of the vessel and treated accordingly ; and in 
the other case rejected from it. In the engines, although the diameters of the 
cylinders were identical, the stroke of the wave vessel was somewhat longer than 
the other, but the diminished effective diameter in the shorter stroke reduced them 
to nearly the same proportion. 
Thus far the experiments given only serve to prove that practically a considerably 
better result has been obtained by a steam-vessel built on the wave principle than 
by a competitor built under conditions that are perfectly identical, in so far as the 
public and the owners are concerned. 
But as regards the purely scientific question, I shall add two other experiments 
with the waye vessel, which furnish data of a more permanent and precise nature— 
one at a higher, the other at a lower velocity. 
Table I1.— Experiments on the Wave Vessel. 

I. Velocity of vessel ...... 15°14 miles an hour. 
wheel ...... 18°17... 
Slipansensecsase neceeerond: 3°03 
II. Velogity of vessel ...... 16°50 miles an hour. 
f° wheel ...... 21°20 . 
SM Seateenyersaccesnensess ec 4°70 
The area of midship section immersed was 89°4 feet. 
The surface of vessel immersed was 3080°0 feet. 
The area of paddle-floats was 26°8 feet. 
The conclusion which I deduce from these last experiments is this, that by means 
of the wave form one may obtain a form of which the resistance shall be repre- 
sented by 1 : 1 
ges 2 A. H.S., instead of oes A. H.S. 
which is the lowest number given in any previous system of construction, A being 
the area of midship section, H the height due to the velocity of the vessel, and 8 the 
weight of a cubic foot of water. 

Specimens of Incombustible Cloth. By James Larro, Dundee. 
Specimens of Incombustibie"Cloth for ladies’ and children’s dresses, manufac- 
tured by Mr. James Latto, Dundee, were exhibited to the Section by Sir David 
Brewster. This cloth will not catch fire either by a spark or even by contact with 
a lighted candle, or fire to such an extent as to injure the person who wears a dress 
made of it. It burns slowly, with agreenish flame, and is speedily extinguished. 
Rain or washing deprives the cloth of its difficult combustibility, and it was with 
the view of directing the attention of chemists to the subject, so as to discover a 
“method of giving the cloth a permanent incombustibility, that Mr. Latto was 
anxious to have his specimens submitted to the Section. 


On Meteorology considered chiefly in relation to Agriculture. 
By the Rev. Dr. Tuomson. 
This was an essay enforcing the importance of meteorological knowledge to those 
“engaged in agricultural pursuits, with numerous suggestions as to courses of ob- 
servation which it would be desirable to institute. 

On Teaching Perspective by Models. By Henry TwIininc. 
_ Mr. Twining exhibited models and demonstrated by figures drawn on glass the 
‘importance of having the perspective plane selected in a proper position to the seve- 
1849. 5 3 
be oc: 
