1843.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



245 



horses, their weights, and structure ; and the large dray horses used hy 

 Messrs. Barclay, Perkins, and Co. did a full average duty as assumed by 

 Goulton and Watt j hut considering the average power of strong and of weak 

 animals, he had adopted 22,0001b. raised 1 foot high as the standard; much 

 however depended on the nature of the work performed. 



Mr. 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 im- 

 portance ; and when extra exertion and muscular action were required, the 

 nearer horses approached to " thorough bred," the greater was the result. 



Mr. Davidson gave the following statement of the work performed by a 

 London brewer's horse per day ; 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. Home stated that Messrs. Tredwell had a contract on the South- 

 eastern Railway, near where Mr. Simms' experiments were made ; they had 

 i.pwards of 100 horses, whose average cost was about 30?. ; 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 South- 

 ampton Railway, which cost them about 25/. each. The same course of not 

 over-working, and 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 necessity 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 con- 

 tract, 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 25?. 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-con- 

 tractors 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 be- 

 longing to Mr. Edwards, the sub-contractor for the excavation of Newton 

 Hill, and those of Mr. W. Tredwell, sub-contractor for the Friar Park Farm 

 cuttings, were purchased from the same parties at prices varying from 20/. 

 to 35/. 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 6/. or 7/. a-piece for them. On the 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 



' In 1837 a disease was prevalent among the horses ; therefore lhat year 

 is omitted. 



e jr ewer horses were bought during the year 1840; the old horses were 

 Utter fed, and harder worked. 



parted with. Having been a good many years in the service of the late Mr. 

 Mcintosh, Mr. Home could state that it never was his system to over-work 

 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 -J tons, was drawn by one horse 

 along a railway 960 feet in length, 260 feet of it being level and the remain- 

 ing 700 feet having an inclination of 1 in 138 ; during 48 working days the 

 number of trips was 1,302, or an average of 27-1 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 23,959,0001b. 

 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 1621b. per ton ; by calculation it was found 

 that the horse raised 39,320 lb. 1 foot high per minute during the eight 

 working hours each day, the useful effect, or net amount of stone carried, 

 being 21,738 lb, raised 1 foot 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 10} cwt. ; he continued doing 

 the same work throughout a whole summer, remaining in good condition ; 

 but a lighter horse was found unequal to it. 



" Description of Lieutenant D. Rankine's Spring Contractor." By Wm. 

 John Maequorn Rankine, Assoc. Inst. C. E. 



This paper describes a contrivance for suiting the action of the springs of 

 railway carriages to variable loads, so as to give the proper ease of motion 

 to a carriage when heavily laden, and at the same time to be sufficiently 

 flexible for light loads. Its effect is to make the strength and stiffness of 

 the spring increase in proportion to the load placed upon it. Each extremity 

 of the spring, instead of supporting a shackle or roller, as in the usual con- 

 struction, carries a small convex plate of cast iron. The form and position 

 of this plate are so adjusted, that when the carriage is unloaded, it bears on 

 the extreme end of the spring, thus allowing it to exert the greatest amount 

 of flexibility ; but as the plate is convex, the more the load increases, and 

 the further the ends of the spring descend, the nearer does the point of 

 bearing of the plate upon the spring approach to the centre or fulcrum, so 

 that the convex plate or contractor tends to diminish the viitual length of 

 the spring in proportion to the load, the result of which is to increase the 

 strength of the spring, in the inverse ratio of its virtual length, and its stiff- 

 ness in the inverse ratio of the cube of the same quantity. The author then 

 gives, in a tabular form, the details and the results of some experiments 

 made on springs of this description, which are similar to those now in use 

 on the Edinburgh and Dalkeith Railway. The springs were 4 feet long, each 

 consisting of ten plates, each \ inch thick, and 2% inches broad. The con- 

 tractors were cast with a radius of \2\ inches, and so constructed as not to 

 act until the load on each spring exceeded 10 cwt., and with a load of 

 30 cwt. they should have contracted the distance between the bearing points 

 to 3 feet 4 inches instead of 4 feet ; by this means the strength of the spring 

 was increased in the ratio of 6 to 5, and its stiffness in the ratio of 216 to 

 125. * The advantages stated to be derived from the use of these springs on 

 the Edinburgh and Dalkeith Railway, and other lines, are, that they afford 

 the same ease of motion to a single passenger as to 40 or 50 in one carriage ; 

 they save wear both of carriages and railway track ; they produce the 

 strength and stiffness requisite for the maximum load with less weight of 

 metal; they are not more expensive than rollers; and they are not offensive 

 in appearance, indeed they would not be observed unless they were pointed 

 out. 



. The President's Conversations. 



Mr. Walker, the President of the Institute of Civil Engineers, gave his 

 annual conversation^, at his residence in Great George Street, Westminster, 

 on Friday 16th, and Saturday 17th ult., extending it to two evenings instead 

 of one, as hitherto, in consequence of the crowded state of the rooms last 

 year, and with his usual liberality to afford his numerous guests ample op- 

 portunity to examine the works of art and science distributed throughout 



9 Since this communication was made, contractors of greater length and 

 increased radius of curvature have been applied, so as to produce a contrac- 

 tion of G inches at each end of the spring when fully loaded, which increases 

 the strength in the ratio of 4 : 3, anil the stiffness in that of 64 : 27. The de- 

 tails of the constiuction of these contractors, with a drawing of them, as 

 applied to the springs of the carriages on the Edinburgh and Dalkeith Rail- 

 way, are given in the addendum to the original paper. 



33* 



