338 SEVENTH REPORT—1837. 
2nd. By compression, or crushing specimens of different 
lengths, and various forms and sizes of base. 
drd. By a transverse strain, and this under different forms 
of section. 
In this last mode of fracture some bars have been broken 
under various temperatures, and others have been loaded for 
a very long time with weights, nearly as large as would have 
broken them at once, and they are still bearing the loads. 
The experiments on the transverse strain (excepting those 
on the Carron iron, No. 2, the Devon, and the Buffery, of 
which I read an account at Bristol) were made by Mr. Fair- 
bairn, who undertook also the experiments on the effects of 
temperature and time. I was desirous that he should try the 
effect of time upon loaded bars, being convinced that it would 
do little or nothing to destroy their power of bearing a dead 
weight; having arrived at this conclusion from experiments 
made in a different way upon malleable iron. As I was pre- 
sent at many of Mr. Fairbairn’s experiments, I may mention 
the great care and ability with which they were made; they 
will form the subject of the next paper. 
The experiments on the tensile and compressive forces of 
the metals, and those on the transverse strain read at Bristol, 
were made by myself and are given below. 
Tensile strength of Hot and Cold Blast Cast Iron.—To 
determine the direct tensile strength of the different kinds of 
cast iron made use of in these experiments, a model was made 
of the same form as I had previously used in some experiments 
on cast iron, of which a notice was given in the Cambridge 
volume of the Association. The castings from this model were 
very strong at the ends, in order that they might be perfectly 
rigid there, and had their ¢ransverse section for about a foot 
in the middle of the form annexed = >. This part, which 
was weaker than the ends, was intended to be torn asunder by a 
force acting perpendicularly through its centre. The ends of 
the castings had eyes made through them, with a part more 
prominent than the rest in the middle of the casting where the 
eye passed through. The intention of this was that bolts pass- 
ing through the eyes, and having shackles attached to them 
by which to tear the casting asunder, would rest upon this 
prominent part in the middle, and therefore upon a point 
passing in a direct line through the axis of the casting. 
Several of the castings were torn asunder upon the machine 
