William Hosking to Faraday   26 January 1835¹

44, Berners-street, Jan. 26, 1835.

Dear Sir, - As you have witnessed the experiment upon the improved or pneumatic system of railway, and expressed a highly gratifying opinion of its merits, I am anxious to be permitted to cite you as an authority on those important points on which you can speak most confidently, and on which alone its practical application depends.

The efficacy of the power is, of course, indisputable; and it is but to witness the experiment, as you have done, to admit that the mode of its application which this improvement embodies is equally simple and certain.

To put the power which nature supplies in action, and apply it to the object, local steam-engines are employed, as these yield the services of the gigantic force of steam in the cheapest possible manner. Local steam-engines possess, moreover, this further important and valuable quality, that the intensity of the force may be greatly varied upon them, so that they may be worked at a low pressure for levels and descents, and be increased in their effect to almost any extent to work acclivities.

The possession of the means of increasing the active force as the occasion may require, obviates the necessity of obtaining a level, or even a near approach to a level; and as it is this necessity which involves the enormous expense of cutting down or tunnelling through hills, and of embanking across valleys for the locomotive system, the advantage of obviating it needs only to be pointed out to be admitted.

In the mechanical construction of the railway, whilst the cylindrical form which is given to the body, and its inflexible continuity, make it independent of artificial foundations, the attachment of the rails to the cylinder upon its horizontal diameter gives them the important advantage of being at once inseparably connected, and totally independent of extraneous or artificial support.

Besides the general stability which the peculiar form and mechanical construction of the improved railway give it, the system upon which it is worked renders it free from any tendency to derangement, since the carriages run along upon the rails with the even and unexciting pressure of the load alone; and this system employs no ponderous locomotive-engine, whose violent concussions might promote any such tendency, nor is the railway burdened with an incumbrance which wastes upon its own unprofitable weight a large proportion of the power it brings.

The attachment of the governor, or external carriage of the travelling apparatus, to the dynamic traveller within the body of the railway, and its connexions with the railway itself, are such as to preclude the possibility of its being thrown off; and as the train of carriages must follow the governor, and every carriage has its peculiar attachment, their security is absolute. Indeed, it appears to me difficult to suppose an accident arising form the railway itself, or from the mode of transit, or that could happen to either, that could have the effect of rendering the carriages insecure, or even affect in the slightest degree their safety.

I do not trouble you with questions as to the cost of formation and construction, as that is a mere matter of estimate; - the fact that the power employed is capable of being increased at pleasure, to overcome acclivities, shows an important saving in the most expensive item; and in working a railway, the difference between the expense of local and locomotive steam- power alone, is so beyond all comparison in favour of the former, that no one at all conversant with the subject will require evidence of the great advantage in point of economy to be derived from its use.

Your confirmation of the correctness of the views herein stated will much oblige,

Dear Sir, | Your faithful servant, | William Hocking [sic].

Michael Faraday, Esq., F.R.S., | &c. &c. &c.