684. REPORT—1904. 
TUESDAY, AUGUST 23. 
The following Report and Papers were read :— 
1. Report on the Tidal Régime of the River Mersey. 
See Reports, p. 318. 
2. The Control of the Nile! By Major Sir Hansury Brown, K.C.M.G4. 
3. A Universal Testing Machine of 300 tons for Full-sized Structural 
Members. By J. H. Wicxsterv, Pres.J.Mech.£. 
The machine will admit a column or strut 88 feet long, 3 feet 3 inches square 
in cross-section. It will admit a beam 3 feet 3 inches broad, 6 feet 6 inches deep, 
and 20 feet between supports. It will shear a bar of mild steel 8 inches by 
22 inches, It will break a steel wire rope 9 inches in circumference. 
It makes autographic stress-strain diagrams in all these tests. The sensibility 
of the machine with a pull of 100 tons is one in 10,000, 
A list was then given of other large machines. 
The purpose of the machine is not simply that of testing the strength of 
material itself, but it is for testing the strength of a full-sized member of any 
structure ; that is, the strength which results from the disposition of the material 
in the sections and in the proportions of, for example, a strut, an eye-link, or a 
beam. The reason for employing a machine for the purpose of making tests 
instead of loading on full loads directly upon the specimen is, that for no reasonable 
cost could you possibly make experiments with heavy loads applied in bulk. 
Three hundred tons of accurate dead-weights would themselves cost about 2,4002. ; 
their application to the specimen would be so tedious that each experiment would 
cost as much in time and in labour as 100 experiments conducted in the machine 
to be described, where the full load is applied through hydraulic pressure and 
balanced by small accurate weights acting through levers and knife-edges. To 
minimise time and labour in making tests on various forms of structural members, 
this machine has been so designed as to be applied, without any change of 
apparatus, either to thrusting strains or pulling strains, and this is accomplished by 
making the straining frame in the form of a large trough, which is pushed forward 
by a hydraulic plunger and which carries with it a straining head capable of being 
locked at any part of its length. This trough, hydraulic ram, and cylinder are 
completely surrounded by a balancing framework of tension rods and cross-heads, 
and this enables the straining cross-head to apply its force to one part of the 
balancing-frame which surrounds it for compression tests, and to another part of 
the balancing-frame for tension tests. Wherever the force may be applied to the 
balancing-frame, it is delivered to the levers and poise weights where it is 
measured, Besides the facility for bringing forces to bear either in compression or 
tension, it is requisite that no labour should be involved in arranging the machine 
to take in long or short pieces, and this is accomplished by mounting the straining 
head upon wheels, so that it can be quickly run to any part of the moving trough 
and locked there by bolts, which can be shot with the same facility that you would 
shoot the bolts in the door of a strong-room. 
An article from ‘Le Génie Civil’ was quoted, with remarks on the machine from 
pen of M. Breuil, Chef de la Section des Métaux du Laboratoire des Arts et 
Métiers. 
4. The Effect of Rapidly Alternating Stresses on Structural Steels.” 
By Professor J. O. ARNOLD. 
1 Published in Public Works, January 1905. 
* Published in the Hngineer, September 2, 1904. 
