F . TRANSACTIONS OF THE SECTIONS. 185 
a Norwegian (Steinitz, p. 41); and the birds sent forth by Noah are thus recalled to 
notice. ; 
The foregoing paper was further illustrated by an original sketch of a Nile boat 
made by a Mahommedan, which strikingly resembled the ‘‘ Heaven-bound ship” de- 
picted by Clemens as a symbol of the “Christian church.” Also by an old sketch 
from the Roman catacombs, in which Noah’s ark is shown as a chest with a man in 
_ it, and a lock and key. Also by a modern drawing of a steam-boat by a Chinese 
+ painter, which contrasted with a sketch of the ‘Great Eastern’ steam-ship. 
On a new Railway Signal, By Dr. Gray. 
The author said the new railway-signal had been tested very satisfactorily upon thé 
Midland Great Western Railway. The qualities which it possessed, and which were 
relied on as establishing its value and efficiency, were,—First, the signa] could be made 
from the guard to the driver and back again with certainty and rapidity. Secondly, 
that the guard and driver should be able to communicate with each other by means of 
_ acode of signals. Thirdly, that in certain cases the signal apparatus should be self- 
acting automatic; for instance, if any accident caused the severance of the train, which 
would prevent any communication between the guard and the driver by the voluntary 
action of either, that notice of the fact would be conveyed to them by the apparatus 
itself. - Fourthly, that there should be no special skill required in order to manage or 
make the signal; what he meant by that was, that it should not be liable to derange- 
ment, and that in case some derangement did occur, the ordinary workmen employed 
on railway works would be able to set the apparatus right or make a new one. Fifthly, 
that there should be always a constant indication before the parties in charge of the 
train that the signal was in working order, so that the guard would not start from the 
station without knowing that the signal was all right and in reliable condition, and 
would not fail him upon the journey. The sixth requisite was, that the communication 
between the carriages should be of such a nature that there would be no serious delay 
in making up the train of carriages, because of the use of the signal. 7 
The author entered at some length into the principles and details of the invention, 
and exhibited a working model, the size of the actual apparatus, and several experi- 
ments were then tried, all of which worked successfully. 
The essential principle of the signal was stated to be the producing, in a metal tube 
of about 3 inch bore, and which was placed along the entire train of carriages, a more 
or less perfect exhaust, and causing the distribution of that exhaust to act on the sig- 
nals. A common exhaust-pump, worked by an excentric on the axle of the guard’s 
_ van, works the pump when the train moves, and instantly exhausts the air from the 
tube. This action causes a piston-head that plays in a little cylinder at the end of 
the long tube which is placed in front of the driver, to be pressed up into the cylinder 
by the external air, and to carry with it and out of view, a red bar or semaphore. 
_ This bar remains invisible when all is right, but the guard, by turning a cock on his 
_ end of the tube like a gas-cock, destroys the exhaust and lets down the red bar or 
danger signal in front of the driver’s eye. The semaphore is so adjusted, that it is in 
et also a weighted lever on a little steam cock to which a whistle is fitted, and when 
it is let down to indicate danger, it turns on steam by its falling, and so attracts the 
driver’s attention by the whistle. The tube from carriage to carriage has a flexible 
pendent and a telescope air-tight connexion. This allows freedom of motion, and on 
the severance of a train the tube is opened, and all the signals given at both ends of 
the train. Similar signals, the steam whistle alone excepted, are placed in the guard’s 
Yan, and the driver or any passenger can communicate with him by opening a stop- 
cock. A little treddle placed near the guard’s foot enables him to test the apparatus, 
d ascertain if the connexions are all right before the train moves. The excentric 
en maintains the exhaust. 
The signals were made through a tube 168 feet in length with the greatest rapidity, 
and the air was exhausted at one end by an air-pump, but by a simple turning of the 
ock the effect of this exhaustion was destroyed, and a red bar or semaphore was 
rown across a little box representing the box beside the driver, and a whistle was 
o made to sound by the same instrumentality. 
‘Se 
