REPORT—1854. 
148 
sary in ft mill where direct action was required, that a fly-wheel should be constructed 
of sufficient size and weight to have, with a small number of revolutions, sufficient 
momentum to overcome the ordinary shocks of rolling large plates of iron. This 
could only be done by increasing the diameter of the wheel to such an extent that 
the rim should have the requisite momentum or velocity of so many feet per minute. 
With this view a wheel has been made of 35 feet diameter, and weighing about 60 
tons, 24 tons of which is disposed in the rim, which is intended to run with a velo¬ 
city of about 4500 feet per minute, at about thirty-eight revolutions. 
Mr. Clay produced and explained the model of a machine used for rolling ta|>cr 
iron, by which an iron bar may be rolled of any length and tapered to any required 
degree. The principle of the action of the machine consists in allowing one of the 
rollers to rise in its bearings by hydraulic pressure. A valve, regulated by a fine 
•crew, permits the water to escape, and thus, as the operation proceeds, the rollers 
become more and more separated, and the iron bar less flattened. By regulating 
the valve, so as to nllow of greater or less escape of the water, the degree of tapering 
can be very accurately adjusted. _ 
Mr. Cullky explained the plans adopted for the transmission of time-signals 
through the electric telegraph wires in connexion with the Observatory at (Greenwich. 
On Ventilation of Ships. Bp J. Cunningham, C.E., F.G.S. 
It is an acknowledged fact by all men practically conversant with the general 
condition of emigrant ships, as regards ventilation, that the means presently adopter! 
t«. effect that important condition are very defective, if not altogether inadequate. 
In h .t v.( itbcr, in calms nnd stormy weather, on board emigrant ships, where so 
many human brines nre usually crowded together, and in spuces proportionally less 
than are allowed for the commonest lodging-houses, the wnnt of such means u 
rOrct n thorough ventilation is painfully and often fatally experienced by the poor 
emigrants. Many instances of those fatal effects might be given from the want oi 
•och means. 
The means now employed for ventilating, not only emigrant ships, but even the 
br*t- appointed mcn-of-wnr or government ships, appear quite inadequate to i 
that great desideratum, nnd it may be safely asserted, that without motive power a 
thorough system of ventilation cannot be carried out on board ships of any class. 
By the application of this power a constant and most effective method of ventua- 
tmn can at ail time* ho carried on. In combination with it also is a simple procc** 
of disinfecting a ship, should an infectious distemper break out, in a most effective 
mann;r - The plan of the engine shown is calculated nt tlirec-horse power, 
and sufficient to ventilate thoroughly a ship of 1500 tons burthen, containing w* 
hundred persons, mid to afford to each person three cubic feet of pure 
minute. Hus supply is effected by two fans, as shown, performing 150 revolutions 
m a minute, thereby forcing the air down the main air-shaft to the side trunk Hoc-, 
whirl, extend along each side of the vessel. Small branch flues to the cabinsi an** 
other part* of the ship requiring ventilation are joined into the main trunk Hue-- 
ha, li is provided w ith sliding or revolving ventilators to regulate the requisite »®° 
of »upply. I he vessel at the top of the section is for disinfccling or for cooliog 
atmosphere. J he tank at bottom is charged with water containing the disinfcciir.B 
fluid, and the truncated cone, which we term a spravor, is inverted with 'tssm 
rnd into the fluid; its upper end spreads out as shown, and is perforated. > 
vev. l rotates rapidly, and the fluid by the centrifugal force is drawn up and ttW*. 
i ut in spray, through which the air must pass into the fanners, thus becoming 
pr, gnat«1 in its passage with the disinfecting material, such as the chloride or» 
or oi hme. In like manner the air could be readily and rapidly cooled to a Io 
p, •• of temperature by placing in the tank a moderate quantity of ice. This may 
applied in the tropics or when required. •• 
The cost of providing a steam-engine, boiler and apparatus complete, 
flu**, 4c., for a ship of 1500 tons burthen, similar to the plans now exhibited, « 
