visit, the average yield of ore, after roasting, was 44 per cent., and the charges thus composed :660 lbs. coal,

520 lbs. ore roasted,

100lbs. lime.

They usually made 40 charges in 24 hours. During the two days that I witnessed the working of the Clyde Works, the number of charges were,

July 4-from 6, A. M., to 6, P. M., 38

from 6, P. M., to 6, A. M., 39 6-from 6, A. M., to 6, P. M., 37 from 6, P. M., to 6, A. M., 40 The yield of the furnace in these four castings was-4 tons, 8 cwt.; 4 tons, 9 cwt.; 4 tons, 6 cwt.; 4 tons, 12 cwt. Total, 17 tons, 15 cwt., for 154 charges,; or, S tons 17 cwt. 2 qrs. each 24 hours.

This result shows that a ton of iron is produced at an expense of 2 tons, 8 cwt. 2 qrs. of coal. The consumption of the heating fire is 8 cwt. Total, 2 tons, 16 cwt., 2 qrs. per ton of iron.

The castings are made every twelve hours. The metal obtained is usually a mixture of No. 1 and No. 2. That which goes first from the hearth is No. 1. These two varieties of iron are distinguished by the small channels which furrow the surface of the metal while cooling.

The tuyeres are hermetically closed round with clay, and as they cannot resist the elevated temperature to which they are submitted, water tuyeres have been substituted similar to those used in the fineries. fig. 3. plate 2, represents the tuyeres employed at the Clyde Works; they are of cast iron, and last various lengths of time, averaging five or six months.

The

furnace; nevertheless there are scarcely any sparks produced by the oxidation of the iron, and the particles that fall are black in the centre, showing that the metal is still covered with a small layer of melted scoria.

The flame issuing from the furnace is of a bright red, while that from the coke furnace, worked with cold air, is of a yellowish colour. This difference of colour is as marked as that which exists between the flame of alcohol coloured by strontia and by baryta.

The pressure of the blast in the air-vessel is two pounds and a half, or five inches of mercury to the square inch. It is sensibly the same near the tuyeres, only the gauge which indicates it is subject to great oscillations. This pressure was formerly three pounds. The opening of the tuyere is three inches,-it was two inches and a half when cold air was used. The quantity of air forced into the furnace is less. The blowing engine, of seventy-horse power, served only three furnaces, now it feeds four with ease. From the dimensions of the blowing cylinder* the quantity of wind, which was 2,827 cubic feet per minute of cold air, is now but 2,120 cubic feet.

The furnaces of the Clyde Works have not been altered since the introduction of hot air. They had been in blast a long time when this new plan was adopted; one of them has been seven years in blast, and the regularity of its operations gives an earnest that it will last a long time.

At the commencement of this report, I have already stated the economy of fuel, and of flux, which had been obtained at the Clyde Works, by the introduction of hot air. [ think it, nevertheless, useful to show the correctness of the estimate by transcribing a statement of the different expenses of manufacture during a month, while cold air was used, and a corresponding month with the use of hot air.

1st week

68 2

18 13 1 13

125 12

THE UNDULATING RAILWAY-IS THE FRICTION OF ROLLING BODIES ACCORDING TO THE TIMES OR THE SPACES?

Sir, Previous to receiving the Number of your Magazine of Saturday last, in which Mr. Badnall appeals to me for an explanation of my opinion, as to whether the friction of rolling bodies is proportional to the times or to the spaces, I had committed to paper the following observations on that point, suggested by the investigations of Mr. R. Stephenson and Mr. Whitehead, and I now, therefore, forward them to you for insertion.

2

I agree with Iver Maciver that Mr. Stephenson's theoretical investigations, or rather his formula, on the undulating railway system, are any thing but satisfactory. I regret, however, that Iver did not go a little more into detail, and treat the subject with a little more gravity, than he has thought proper to do. Mr. Stephenson asserts, that if a body be moved from a state of rest upon a horizontal plane, and be acted upon by a continued force d, after passing over a space s, the final velocity acquired will be d s. This will, no doubt, be true, if d is a constant force like that of gravity, so as to produce an uniform acceleration of velocity; and if this can be proved to be so in the case of locomotion, produced by steam, it would, certainly, go a great way in diminishing some of the supposed advantages that might be expected from Mr. Badnall's undulating system. For, as Iver Maciver justly remarks, as s in creases, so does ✔ds;" so that if the motion be continued for a sufficient length of time, any velocity required is attainable on the horizontal line. But Mr. Stephenson himself, in his practical remarks (No. 603, p. 391,) asserts that this cannot be done. He states-" when the velocity of these engines exceeds that for which they are calculated, the steam acts less forcibly on the pistons, and thus produces an absolute loss of power,' &c. How Mr. Stephenson can reconcile this observation with ads being the final velocity obtained on the horizontal line, is somewhat beyond my comprehension. Again, Mr. Stephenson states (p. 389)," the body will arrive at the summit of each undulation with a velocity due to the action of the force d,

which is √ds." Iver has, certainly, mistaken Mr. Stephenson's meaning here; for he (Iver) supposes that Mr. Stephenson meant that ds is the velocity acquired at the point B. But from what follows, it is plain that Mr. Stephenson allows that √ds is the velocity the body still retains on arriving at the point C by the undulating line; for, he says, "if the body were actually propelled by the force d, more efficiently on the one surface than on the other, it must arrive at the C with different velocities," &c.

Mr. Stephenson concludes his theoretical investigations with the following incongruous deduction :

"The above considerations lead me to. conclude, that theoretically there is neither advantage nor disadvantage in the use of an undulating surface for a line of railway."

Well, let us try and estimate the precise value of this deduction.

We shall grant Mr. Stephenson, that when a body is urged on by a force d (d being considered an uniform force) on the horizontal plane AO C, it will arrive at the point C with the velocity √ds. We shall also grant, that when the body moves over the undulating line A B C, it arrives at the point C with the same velocity ds. But, says Mr. Stephenson, "the velocity given by the force n g in descending is lost in ascending." Now, although we should grant that the force n g is lost in ascending, still it has produced a certain effect upon the undulating line, which Mr. Stephenson has most unaccountably overlooked, namely, in the element time, which, I trust, he will allow is of some importance.

Suppose A C is 1 mile, or 5,280 feet; Bo 20 feet; and suppose a carriage starts from A,and is urged on by a constant force d, and arrives at C (either on the horizontal line A O C, or the undulating line A B C), with a velocity there obtained of 24 miles per hour, or 35 feet

(s being .11733, and n g

.24369. Therefore, the

sum of the two forces n g+d=.36102= P, and the velocity acquired at B will be √Ps√.36102 × 528043.66; and the time in descending through A B will 2 A B_52 80 120 seconds. Also, 43.66

be

43.66

the time in moving up the ascent B C will be 5280(43.66 + 35.2) = 667% seconds..the whole time in the undulating line is 1874 seconds, or 3 minutes 7 seconds. The time in the horizontal line is exactly 5 minutes; that is, there is a saving of time to the extent of 372 per cent. gained by the undulating line, and, as Iver Maciver remarks, a like saving of power takes place. Or if we adopt an uniform velocity, which Mr. Stephenson strongly recommends, and suppose the carriage to move over the horizontal line A O C, with an uniform velocity of 24 miles per hour, the time in this case will be 2 minutes 30 seconds. Then, from Iver Maciver's formula, d+

2

gsn (2s in this case being 5280 feet), is the average velocity from summit to summit, which, being calculated, 52 80 is 53.13 feet per second..

=992/ 53.13 seconds is the time in moving over the undulating line A B C; and in this case there is again a saving in time of 34 per cent. in favour of the undulating line.

My old friend, the Lieutenant of Engineers, states (No. 597, p. 261,) that he has read Mr. Whitehead's article on the undulating railway question, and that he has every reason to believe that he (Mr. Whitehead) has managed all his equations with skill; still he is afraid the results are not true, because he has founded his solution upon what he conceives to be false principles, viz. that friction is the same at all velocities; while I (Kinclaven) have grounded my calculations on the principle, that friction is proportionate to the times. Your very able Swiss correspondent, Lewis Frend, in the postscript to his article (No. 602,) says, "that if the Lieutenant of Engineers will reconsider what he has

said about the principles laid down by Kinclaven and Mr. Whitehead, in their respective solutions of the undulating railway question, he will find that, although differently enunciated, they are fundamentally the same." I must state, that I am of the same opinion with Mr. Frend. For, if friction is proportional to the times-suppose f is the friction for 1 second, then t f is the friction for 6 seconds, and this must be true by hypothesis, whatever the velocity may be; that is, whether the velocity is 10 or 50 miles per hour. Therefore, I must say that Mr. Whitehead was right in saying that friction is the same at all velocities. In fact, if he is wrong, so am I. Mr. Badnall has often stated, that as the velocity increases the friction diminishes; and he is also right in the sense he meant to be understood; that is, when we compare friction with the spaces passed over. Thus, suppose a body moves over a line of 10 miles in 1 hour, and that the whole amount of friction is f, and if the same body moves over a like line of 20 miles in 1 hour, the times being equal, the amount of friction upon the 20 miles will also be f; but if we compare the friction with the spaces passed over, we would say that the friction in the latter case is only one-half of that in the former.

In justice, however, to Mr. White head, I certainly agree with the Lieutenant of Engineers, also with Mentor, that he is an able mathematician, and that in the mathematical part of his article he has shown much skill and ingenuity; although, as Mentor justly observes, there is nothing in that part of his communication which is against the undulating system, or rather the most important part of it-for, so far as time is concerned, it is decidedly in favour of it. But when Mr. Whitehead throws aside the mathematical robe, and assumes that of the special pleader, then, I must say, I cannot agree with him; and more particularly so, when he attempts to show that Mr. Badnall's system in no case offers any inducement for its adoption. So says Mr. Stephenson, in his last deduction; but, if I do not myself labour under some great delusion, I trust that I have proved the contrary. I am, Sir, yours, &c. KINCLAVEN.

April 27, 1835.

Sir,In your valuable Magazine, No. 598, I perceive an account of a pistol-whip. Of the kind of locks made use of in such cases I am not aware; but I have a percussion-lock that I constructed some time ago that may be used to advantage, and which is constructed on what I take to be rather a novel principle. The following description of it may be, therefore, not unworthy of a place in your widely circulating pages:

Fig. 1 is a spiral steel spring, 2 inches long, and half an inch in diameter; size of the steel by

Fig. 2 is a section of the lock complete; AA is a copper tube, in which the spring is fixed; oo the spring; b a bolt that passes through the interior of the spring, the large end of which

forms the striker;f is the catch, which, when the handle P is drawn back, catches into the holes 1 and 2, that form the half cock and full cock; g is the spring to the catch.

It will be observed, that when the small nob e is pressed upon, the bolt will be freed from the catch, and the part w forced against the cap by the main-spring o o; k is a flanch to screw it on. The large handle, shown in the sketches, is that of a walking stick, in which the lock is fixed. Fig. 3 is the lock complete.

I am, Sir,
Your obedient servant,
JOHN THOMAS.

Redlake, Wellington, Salop,

March 12, 1835.