102 
THE NECESSITY FOR LEVELS OBVIATED; 
OPINION OF PROFESSOR FARADAY. 
Mr. Hocking to Professor Faraday. 
44, Berners-street, Jan. 28, 1835. 
Dear Sir, — As you have witnessed the ex- 
periment upon the improved or pneumatic 
system of railway, and expressed a highly 
gratitying opinion of its merits, I am anxious to 
be permitted to cite yon 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, in- 
disputable ; and it is but to witness the ex- 
periment, as you have done, to admit that the 
mode of its application which this improve- 
ment 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 im- 
portant and valuable quality, that the inten- 
.sity 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 in- 
creased 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 tunneling through 
bills, and of embanking across valleys, for 
the locomotive system, the advantage of ob- 
viating it needs only to be pointed out to be 
admitted. 
In the mechanical construction of the rail- 
way, whilst the cylindrical form which is 
given to the body, and its inflexible conti- 
nuity, make it independent of artificial found- 
ations, 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 in- 
dependent 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 rail- 
way burdened with an incumbrance which 
wastes upon its ov\m unprofitable w'eight a 
large proportion of the power it brings. 
The attachment of the governor, or exter- 
nal carriage of the travelling apparatus, to 
the dynamic traveller within the body of the 
rail way, and its connexions with the railway 
itself, are such as to preclude the possibility 
of its being thrown off: and as the train of 
carriage 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 
from tlie railway itself, or from the mode of 
transit, or that could happen to either, that 
could have the effect of rendering the car- 
riages insecure, or even affect in the slightest ' 
degree their safety. 
I do not trouble you with questions as to 
the costs of formation and construction, as ] 
that is a mere matter of estimate the fact 
that the power emiiloyed is capable of being 
increased at pleasure, to overcome acclivi- 
ties, 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 be- 
yond 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. 
Michael Faraday, Esq., F. R. S,, 
&c. &c. (Sec. 
Professor Faraday to Mr. Hocking. 
Royal Institution, Feb. 3, 1835. 
My dear Sir, — The points in your letter of the ! 
26th of last month, which you put to me for an 
opinion, are such that I have no hesitation in 
agreeing with you upon them. 
To enumerate briefly these points : — the prin^ 
ciple of communication of power is correct — ■ 
the use of local steam-engines is highly ad- 
vantageous, both for cheapness of force, and 
capability of varying it when required — the 
necessity for levels will, I presume, tlierefore 
be greatly obviated— the association of cylinder 
and rail is such that the whole road must (with 
sufficient thickness in the cylinder) have great 
strength and firmness — the absence of locomo- 
tive-engines removes much of the cause of de- 
rangement which the road would have to sustain 
— and 1 do not see how the governor and car- 
riages can leave the railway. 
You know my objection to giving a general 
opinion ill reference to the profitable application 
of the plan in question ; but 1 may here add, 
that the reserve I feel originates simply in my 
possessing no practical knowledge of the con- 
struction, expense, and profit of ordinary rail- 
roads. 
I am, my dear Sir, 
Very truly yours, 
M. Faradav. 
William Hocking, Esq. F. A., 
&C. &C.&C. 
