Imagens da página
PDF
ePub

a certain quantity of this foul air is thrust into the station by the train as it enters the further end of the tunnel. This foul air, being heated, slowly ascends, filling the streets and neighboring houses.

The stations are nothing more than dwarf ventilating shafts in which the passengers are partially stifled previous to the completion of the process in the tunnel.

Having stated the conditions of the structure, let us consider what is required to be done.

First, we have a certain quantity of foul air to get rid of without harm or annoyance to the public. Secondly, the stations must be kept so clear as to allow of passengers using them with comfort. And thirdly, circulation of air should be maintained in the tunnels, which should be kept as sweet as possible, not only for the sake of the passengers, but for the workmen also, and for the greater security of the public against accidents.

It seems to me that these objects will be best accomplished by reversing the present system, turning the stations into downcast

shafts, and drawing the foul air away at the middle of the tunnels.

A little consideration will show how a series of tunnels might be connected together by what might be called air sewers, and the foul gases led to one or more pumping stations, there to be forced up high chimneys.

The pumps might be either air pumps, such as are I believe used in some Belgian collieries, or machinery similar to Nixon's ventilator, or one of the many kinds of fan.

Some of these machines are very powerful. At the navigation pit, near Aberdare, Mr. Smyth gives the theoretical quantity of air expelled per minute, by one of Nixon's machines, at 166,000 cubic ft. In Belgium many fans of enormous power are at work ventilating coal mines.

The chief difficulty is the expense, but I submit this ought not reasonably to stand in the way.

I believe, however, that a plan could be found, which would accomplish the object at no very extravagant outlay.

I have said nothing about ventilating

ordinary railway stations,--first, because it is difficult, if not impossible, to apply any system to a building which sometimes consists of but one wall, and a part of a roof; and secondly, when the station is of greater pretention, it is almost always open at both ends, and has usually a great deal too much air in it already.

Free escape for steam must be provided, and I think a good example of roof for this purpose was shown, to those of the members who visited the Great Eastern Railway extension works, on Friday last, at the low level station at Shoreditch.

In conclusion, I would again insist on the deep importance of the subject especially to Engineers and Architects. The limits of my space, not to mention other causes, have, I am well aware, prevented justice being done to it; but the object of a paper like this, is more to put forward sound principles and throw out ideas, which may when opportunity requires be worked out to good purpose, than to lay down schemes to meet every or any particular

case.

All scientific men acknowledge the necessity of ventilating dwelling-houses and buildings such as are herein mentioned, but with the general public it is unfortunately far otherwise, and one of the greatest difficulties to be encountered in the progress towards a complete and perfect sanitary condition is this inertia of those most interested. Difficulties are, however, only made to be overcome, and it is in the hope of doing something, however little, towards overcoming this particular difficulty that I venture to trespass further on the patience of the reader, and I propose to confine these remarks to the sanitary condition of our houses as being the subject of most immediate importance to the general public, for ventilation of such structures as factories, railway tunnels, and sewers, though of great moment, must be left in the hands of the Engineer who designs them, each case being treated upon its own merits and with due regard to its peculiarities. All the public can do in such instances is to insist that there shall be ventilation of some sort.

All persons readily admit as a truism, that they cannot live without air, but, unfortunately, they seldom get much beyond the bare admission. Air is not treated by them as a substance requiring space as solids or liquids do, and means of passage into, or out of, rooms, churches, etc., just as much as water requires pipes or channels to allow it to flow into or out of reservoirs. With most persons air seems to be an abstract idea rather than a substance of vital consequence to the whole living creation.

I have stated in the paper that air, which has once passed through the lungs is unfit to be respired again, just as unfit as any other substance which has once passed through the system is to be used, as it were, over again. So that, were there no other source of contamination to the air of a building, ventilation would be rendered necessary by the very presence of living beings. As it is, however, there are so many other evil influences at work in most houses and other buildings that the necessity is made far more absolute.

It is usually only in times of panic, caus

« AnteriorContinuar »