metal would sustain the sum of all the forces equal to half the diameter. The rule given as to its being equal to the semi-circumference is absurd. Suppose the circle drawn out flat, or oval, would not the points of rupture be at the extreme ends? And would any engineer in his senses say two plates attached at their ends were as capable of withstanding internal pressure as when formed into a cylinder ?

I am, Sir, yours respectfully,

HENRY DEACON.

St. Helen's Crown, Sheet, and Plate Glass Works, Lancashire, July 11, 1843.

INSTITUTION OF CIVIL ENGINEERS. MINUTES OF PROCEEDINGS-SESSION 1843. "Results of the application of Horse Power to raising Water from the working shafts at Saltwood Tunnel, on the South-Eastern Railway, in 1842," By Frederick William Simms, Esq., M. Inst. C. E.

This tunnel is driven in the middle bed of the lower green sand, between which and the surface of the ground is interposed only the upper bed of the same stratum; but in sinking the eleven shafts for the work, it was found that at the level of the top of the tunnel the ground assumed the character of a quicksand, saturated with water, in such quantity that it could not be reduced by manual labour. Under these circumstances horse gins were erected for drawing the water by barrels, containing one hundred gallons each, weighing when full about 1310 lbs.

The engineer's intention was to drive si

multaneously from these shafts, in the direction of the tunnel, an adit or heading, to carry off the water; but the earth, which was sand mixed with fine particles of blue clay, was so filled with water as to become a mass of semi-fluid mud, great exertions were therefore necessary to overcome the water, without erecting pumps. At first this was accomplished by making each horse work for 12 hours, and then for 8 hours per day, allowing one hour for food and rest; as the water increased it became necessary to work night and day, and the time of each horse's working was reduced generally to 6 hours, and sometimes to 3 hours. As all the horses were hired at the rate of seven shillings per day, the author, who had the direction of the works, ordered a daily register to be kept of the actual work done by each horse, for the double purpose of ascertaining whether they all performed their duty, and also hoping to collect a body of facts relative to horse-power which might be useful hereafter. This detailed register, which was kept by Mr. P. N. Brockedon, is appended to the communication.

The author gives as a proposition, "That the proper estimate of horse-power, would be that which measures the weight that a horse would draw up out of a well; the animal acting by a horizontal line of attraction turned into the vertical direction by a simple pulley, whose friction should be reduced as much as possible." He states that the manner in which the work was performed necessarily approached very nearly to these conditions; and after giving the principal dimensions of the horse gins, he analyzes each set of experiments, and by taking the mean of those against which no objections could be urged, he arrives at the following results :

raised 1 foot high in one minute.

ditto.

ditto.

ditto.

Of these results he thinks the experiments for 6 hours and for 3 hours alone should be adopted as practical guides, all the others being in some degree objectionable.

Mr. Palmer said, it should be understood, that in stating 33,000 lbs. raised one foot high in a minute, as the measure of the power of a horse, Boulton and Watt had not intended to fix that as the average work which horses were capable of performing: they had taken the highest results of duty performed by powerful horses, in order to convince the purchasers of their steam-engines that they received all that had been contracted for.

He had made some experiments on the amount of work performed by horses tracking boats on canals: on the upper end of the mast of a boat a pulley was hung; over this the towing rope was passed, with the means of suspending to its extremity given weights, so as exactly to balance the power exerted by the horse.

The results arrived at by these means were so various, that he could not deduce any average conclusions; as the power exerted varied between 30 lbs. and 120 lbs., the power diminishing as the speed was increased he thought that 23 miles was too high an average estimate, and that it should not exceed 2 miles per hour.

Mr. Field remarked that in all estimates of horse-power, the speed was considered to be at an average of 2 miles per hour, and all experiments were reduced to that standard.

Mr. Hawkins said, that some years since, he had made numerous inquiries respecting the work done by horses in drawing upon common turnpike roads, and found, that four good horses could draw an ordinary stage coach, with its complement of passengers, eight miles a-day at the rate of ten

The horses were supplied by Mr. Richard Lewis, Folkstone, Kent.

miles an hour; that if they run stages of ten miles in the hour, the horses must rest one day in each week; that good horses, so worked, would last only five years, each house drawing about half a ton; he had been informed by waggoners, that good horses would walk, at the rate of 24 miles per hour, for twelve hours out of the twenty-four, making 30 miles a-day, and that they would continue to do such work, day by day, each horse drawing one ton, for many years, provided they had not been worked hard when young.

Mr. Gravatt observed, that although there might exist some hesitation in receiving these results of work actually performed, as a general measure of a horse's power, yet as engineers frequently required to know what could be performed by horses, when employed for short periods, in works of haste or difficulty, he thought that the experiments were useful, and would form good data for reference. He was sorry to observe that in too many cases, an idea was prevalent, that it was cheaper to work a small stock of horses to death, than to keep a large number and to work them fairly; the results which he had been enabled to arrive at, were perhaps not a fair value of a horse's work, continued for any length of time, at the best rate of economy, for both the contractor and the employer.

The President believed that however, in cases of emergency, which he allowed did occur in engineering works, the forced system of labour mentioned by Mr. Gravatt might be tolerated, he was convinced that it was not the most economical, but on the contrary, humanity and economy would be found to go hand in hand.

It would be desirable to know the average speed at which the different rates of work had been performed; this was essential in order to found any calculation upon the results given. Coach proprietors calculated

that, at a speed of 10 miles per hour, a horse was required for every mile going and returning, so that one horse was kept for every mile of road. Now supposing a four-horse coach, with an average load, to weigh 2 tons, the load for each horse was 10 cwt.; whereas, in the case of a horse drawing a cart, the gross load frequently amounted to 2 tons, but the speed was reduced to 2 miles per hour, at which pace he conceived that 16 miles per day might be considered a fair day's work; this, therefore, was double the distance with four times the load, or eight times the coach-work, but with a heavier horse.

The law that the quantity of work done was as the square root of the velocity, or as the cube root of the velocity in equal times, was confined to work upon canals, or bodies moving through water.

Mr. Rennie had tried some experiments on the force of traction of the boats on the Grand Junction Canal. The towing rope was attached to a dynamometer which had previously been tested by weights.

The horse, although urged at first starting, was afterwards allowed to fall into his natural speed, which was 24 miles per hour on the average of 20 miles. The maximum speed was 4 miles, and the minimum 2 miles per hour. The dynamometer indicated an average of 108 lbs., which was capable of overcoming the resistance of the loaded barge of 25 tons, being in the ratio of 1.500. The weight of the horse was about 11 cwt.

He had also tried many experiments upon a fast boat lent to him in 1833 by the late Colonel Page. These experiments were principally made in order to ascertain the comparative resistance of vessels moving through water at different velocities, and the Grand Junction Canal afforded a convenient opportunity of undertaking them.

The boat was 70 feet in length, 4 feet in breadth, and drew 9 inches of water.

The traction indicated by the dynamometer the following resistance :

Two horses were employed in these experiments.

Stakes were fixed near the margin of the canal, so as to ascertain the rise and fall of the wave caused by the boat in passing; and it was observed that when the boat passed with a velocity of from 4 to 6 miles per hour, the rise of the wave was 5 inches, and the fall 5 inches, making a wave of 10 inches in depth; and when the velocity was 114 miles, the rise was reduced to 2 inches and the fall to 2 inches.

Great difference existed in the power of horses, their weights, and structure; and the large dray horses used by Messrs. Barclay, Perkins, and Co. did a full average duty as assumed by Boulton and Watt; but considering the average power of strong and of weak animals, he had adopted 22,000 lbs. raised 1 foot high as the standard; much however depended on the nature of the work performed.

The Hon. Charles Wood remarked that although, on an emergency, it might be necessary to work horses to the extent which had been mentioned, it had always been found more economical to feed them well, and not unduly to force the speed, the weight drawn, or the hours of labour. By the recorded experiments on ploughing, which were tried at Lord Ducie's and by Mr. Pusey, it was shown that any increase of speed diminished the amount of work done, in a greater ratio than it was affected by an increase of the load. In drawing loads the weight of the animal was a point of considerable importance; and when extra exertion and muscular action were required, the nearer horses approached to thorough bred," the greater was the result.

Mr. Davison gave a statement of the work performed by a London brewer's horse per day (see p. 141); the cost of feed and of wear and tear per horse per annum, being derived from actual experience among a large number of horses at Messrs. Truman, Hanbury, and Co.'s brewery.

The feed, &c. is supposed to have cost the same per quarter, per truss, &c. each year.

Mr. Horne stated that Messrs. Tredwell had a contract on the South-Eastern Railway, near where Mr. Simms's experiments were made: they had upwards of 100 horses, whose average cost was about 301; they were worked 10 hours per day, and were well fed, so that their value was but little reduced, and they were eventually sold for nearly the same prices as they originally

cost.

These contractors had about 400 horses on the Southampton Railway, which cost them about 251. each. The same course of not over-working, and of feeding them well, was

pursued from motives of economy; and they found it answer.

It was Mr. Jackson's practice to keep so many horses for his work as not to be under the necesity of working them more than 10 hours per day: he gave to each a peck of corn a-day; by this means he has been able to keep up their value.

On the Chester and Crewe Railway he had about 300 horses at work, and towards the end of the contract, owing to circumstances over which he had no control, he was obliged to work them 14 or 15 hours per day; and in the course of four months horses that had been worth 257. were so reduced as not to be valued at above 71. He is a great advocate for steady work and good keep.

On the Tame Valley Canal there had been sometimes between 300 and 400 horses, but as the work was nearly finished many had been sold. Those sub-contractors who had kept a sufficient number of horses for the work, so as not to have them in harness more than 12 hours per day, had realized nearly the same prices they had given for them in the first instance.

The horses belonging to Mr. Edwards, the sub-contractor for the excavation of Newton Hill, and those of Mr. W. Tredwell, subcontractor for the Friar Park Farm cuttings, were purchased from the same parties at prices varying from 201. to 351. The former had been acting on the principle of getting out of the horses all he could, working them frequently 15 and 16 hours at a time; and the consequence was, that all his stock was in bad condition, and he would be glad to get 61. or 71. a-piece for them. On the

In 1837 a disease was prevalent among the horses; therefore that year is omitted.

+ Fewer horses were bought during the year 1840; the old horses were better fed, and harder worked.

other hand, Mr. W. Tredwell, who was an excellent horse-master, and who did not work his horses beyond their strength, would be able to sell them for about as much as he gave for them,-indeed he had done so already for those that he had parted with.

Having been a good many years in the service of the late Mr. McIntosh, Mr. Horne could state that it never was his system to overwork his horses. It did sometimes happen that there was no alternative, but the deviation from the regular rule in every instance showed that his system was founded on right principles. The over-worked horses were most liable to disease, and the time lost by illness formed an important item; whereas there were plenty of instances in which horses that had worked their regular 10 hours per day, and had been properly fed, had worked for five or six years without losing a single day by illness. On the whole, he felt convinced that, both on the score of humanity and economy, the horse was the more valuable servant when treated with kindness.

Mr. Beardmore said that a case had occurred in a work near Plymouth which he believed would give the fair value of the work actually performed daily by a horse for a considerable period.

A quarry-wagon, weighing 2 tons, carrying an average load of stone of 5 tons, was drawn by one horse along a railway 960 feet in length, 260 feet of it being level and the remaining 700 feet having an inclination of 1 in 138: during 48 working days the number of trips was 1,302, or an average of 97.1 trips each day; the time of performing each trip was 4 minutes, or at a speed of 2.72 miles per hour; and the total weight drawn, including that of the wagons, was 23,959,600 lbs.

Repeated experiments proved, that upon the incline of 1 in 138, the wagons in their ordinary working state would just remain stationary, the friction was therefore assumed to be 16-2lbs. per ton; by calculation it was found that the horse raised 39,320 lbs. foot high per minute during the eight working hours each day, the useful effect, or net amount of stone carried, being 21,738 lbs. raised 1 foot high per minute. This difference between the work done and the useful effect, arose from the necessary strength and weight of the wagons.

The animal employed was a common Devonshire cart-horse, eight years old, 15 hands high, and weighed 104 cwt.; he continued doing the same work throughout a whole summer, remaining in good condition; but a lighter horse was found unequal to it.

ELECTRO-TELEGRAPHY. — LIEUT. WRIGHT

IN REPLY TO MR. COOKE.

Sir,-Allow me to offer a few remarks, in reference to Mr. Cooke's letter in your 1043rd Number (5th inst.) I observe that his "intention is not to enter upon the question" (discussed in your review of Mr. Finlaison's work)" in a moral point of view." Surely this is very much like " Hamlet, with the Prince of Denmark omitted;" for your review treats principally of the propriety, in the "moral point of view," of Professor Wheatstone's conduct to Mr. Bain. But let that pass.

Mr. Cooke says he "knows the evidence advanced by Mr. Finlaison to be capable of direct contradiction on many essential points." Now the evidence, so far as it concerns Mr. Wheatstone, consists principally of facts, supported by official and other written evidence, which admit of no contradiction; and if these facts-be the "many' or few-cannot be contradicted, of what avail are differences on minor points? Besides, Professor Wheatstone does not himself deny them.

66

Mr. Cooke says that Mr. Bain and his co-patentees are not the LEGAL proprietors of the disputed inventions, as we only secure particular forms;" meaning, I presume, that we confine our claims to our own inventions. To be sure we do: for we have not such consummate assurance as to claim

any thing else. WE neither claim Mr. Wheatstone's five wires, nor his arrangement of the deflecting needles; nor yet Mr. Cooke's own long poles, nor his raw goosequills. We do not claim Davy's electromagnet escapement, nor Ronald's disks, nor Buzenguger's wheel and propellers: neither do we claim anything so ridiculous

as a right to prevent others from constructing Electric Telegraphs different from our own. We pretend to no right of the kind. The public are at perfect liberty to construct as many telegraphs as they please, so long as they infringe no legal patent of ours.

It is quite true, as Mr. Cooke states, that Mr. Bain did exhibit his original Printing Telegraph, and thus made it public property; but Mr. Cooke knows, also, that this was done to prevent its being purloined and made private property of. He must have seen this prominently mentioned in Mr. Finlaison's work.

Mr. Cooke is incorrect when he states that we deflect the wire instead of the needle, as a colourable evasion of Messrs. Cooke and Wheatstone's patents. We deflect the multiplied coil, and fix the magnet, or magnets, because we find a much greater power is gained thereby than by any other arrange

ment.

Mr. Finlaison admits no such thing as that Mr. Wheatstone had independently conceived the idea of either Electric Clocks or Printing Telegraphs. What he admits is, that the Professor borrowed his ideas of these things from the work of Mr. Ronald, and the Recording Telegraphs of Mr. Davy and Professor Morse, and that he did not know how to carry the ideas out until he saw Mr. Bain's models. A very different thing this to independent invention.

I have no interest in the legality of Mr. Bain's patent for Electric Clocks; but I happen to know that the Professor was served with a notice of injunction, in January, 1840, which prevented him from exhibiting his imitation of them at the Adelaide Gallery.

I have an interest in the legality of Mr. Bain's patent for Printing Telegraphs, and I know these (as well as his Clocks) have been exhibited for three years at the Polytechnic Institution, and that Messrs. Cooke and Wheatstone have never attempted, by LEGAL means, to prevent it.

If Mr. Cooke will digest as well as read the work he has attempted to criticise, he will find, at page 25, that "the established fact" of an increased number of plates producing an increased intensity of current, has proved no "stumbling block," but, that a number of plates are recommended when considerable power is required. Allow me to point out that Mr. Bain's last discovery is the method of generating the electric current by the moisture of the earth without galvanic batteries, as well as conducting it through half the circuit by the same agency. In reference to the supposition that a ton of copper in the Thames, and two tons of zink in the Mersey, would if connected by a capa