"I cannot now attempt to enter into the minutiae of this part of the subject, because it would involve a complete revision of all the original plans, and numerous considerations which could not now be fairly weighed. For the purpose, however, of carrying out the comparison regarding capital in this particular ease, we may suppose that a saving of 900,000 might have been accomplished in the original design, by the application of the atmospheric system, still, it would only have been a transfer of expenditure from excavations, tunnels, and bridges, to steam engines and pipes; the ultimate capital would thus have been the same.

* Mr. Stephenson takes 33,0001bs as the standard of horse power, but Mr. Samuda takes 66,000; therefore, the engine which Mr. Samuda reckons at 100 horse power, Mr. Stephenson estimates as 200 horse power, so that the actual difference in the estimate of the power required to exhaust the pipe is only as 100 to 125.

"If we now take some other lines of railway, with the view of ascertaining how far their cost could have been diminished by the application of the atmospheric system, we shall find that as the surface of the country becomes more favourable, the economy in construction entirely disappears, and when we arrive at a perfectly plain country, such as exists in the eastern counties of England, where few provisions are required in the form of excavations, tunnels, and bridges, the application of the atmospheric system would certainly double the original cost where a double line of rails is employed. The Grand Junction railway is a case where no reduction of original outlay could have been effected, since the gradients already conform to the natural surface of the country throughout a very large proportion of the whole line. The adoption of the atmospheric system in this case would therefore have caused a very large augmentation in the capital of the Company, probably as much as 8,000 per mile, being the difference of cost between the two descriptions of power."

Mr. Stephenson next proceeds to give an approximate statement of the cost of working the two systems, excluding such items as are common to both; but he observes, that "while the cost of the locomotive power is taken from the accounts of the company, - the principal items, and only those, which may be taken as certain in the cost of the atmospheric system, are taken into the account in the comparative statement; in the latter, many minor expenses in the absence of experience must unavoidably be omitted; thus giving some advantage in the comparison to the atmospheric system."

"The expense of locomotive power upon the London and Birmingham railway for the year 1843, was as follows:-

Wages of engine drivers and firemen....................................................

9,673

Coke.....................................................................................................

25,541

Oil, hose, pipes, and fire tools, pumping engines and water

4,099

Labourers and cleaners, waste and oil.......................................................

4,194

Repairs of engines and tenders................................................................

12,521

Coals and fire-wood, expenses of stationary engine at Wolverton, repairs of buildings, gas, and incidental charges................................................................................................

3,172

Superintendent, clerks, and foremen's salaries, and office charges...................................................................................................

4,634

63,834

"The expense of working the atmospheric system for one year, I estimate approximately as follows: -

Wages of engine men ..................................................... 64 at 6s.

10,512

" stokers ............................................................ 64 at 3s.

The same during the night ..............................................................

10,512

Coal, 172 tons per day, at 9s. .........................................................

28,332

Oil, hemp, tallow, and repairs at 5 per cent. on cost of engines .....................................................................................

20,000

Superintendence, same as locomotive ............................................

4,634

Annual cost ..............................

73,990

This statement, in Mr. Stephenson's opinion, sufficiently establishes the fact that the cost of working the London and Birmingham railway, or any other line with a similar traffic, by the atmospheric system, would greatly exceed that by locomotive engines.

Having concluded his observations upon the question of power, original outlay, and cost of working, the two latter having reference chiefly to the London and Birmingham railway, he proceeds: "I will now offer one brief remark on the application of the atmospheric system to lines where the traffic is of very moderate extent. The London and Birmingham railway having an unparalleled traffic, it is one of the best cases, in a general point of view, to which the atmospheric system could be applied. Let us now conceive it applied to a case of an opposite character - for example, the Norwich and Yarmouth railway, which has cost about 10,000 per mile, including stock and every appurtenance. This line passes over a country in which the application of the atmospheric system could have effected no economy whatever in the formation of the line, which has not exceeded a cost of 8,000 per mile. The application of a single line of the atmospheric apparatus would, in this instance, have added at least 5,000 per mile, which upon 20 miles, the length of the railway, would amount to 100,000. The mere interest of this sum, at 5 per cent., is 5,000 per annum; whereas, the actual working of this line, including maintenance of way, booking offices, porterage, and all other constant traffic charges, has been let for 7,000 per annum; being only 2,000 above the bare interest of the extra capital which would be required to lay down the atmospheric apparatus, an amount which would be quite inadequate to meet the wear and tear of the machinery alone, leaving nothing to meet the current cost of working.

Here, therefore, we have a case where the country is favourable, the original capital small, and the traffic moderate, where the cost of the atmospheric system would be so burthensome as to render it totally inapplicable."

Mr. Stephenson sums up in the following manner: -

1st. That the atmospheric system is not an economical mode of transmitting power, and is inferior in this respect both to locomotive engines and stationary engines with ropes.

2d. That it is not calculated practically to acquire and maintain higher velocities than are comprised in the present working of locomotive engines.

3d. That it would not, in the majority of instances, produce economy in the original construction of railways, and in many would most materially augment their cost.

4th. That on some short railways, where the traffic is large, admitting of trains of moderate weight, but requiring high velocities and frequent departures, and where the face of the country is such as to preclude the use of gradients suitable for locomotive engines, the atmospheric system would prove the most eligible.

5th. That on short lines of railway, say four or five miles in length, in the vicinity of large towns, where frequent and rapid communication is required between the termini alone, the atmospheric system might be advantageously applied.