TRANSACTIONS OF THE SECTIONS. 201 
absorbed and chemically combined with the atoms of the gas with 
which they respectively come into contact. Again, that the effecting, 
by means of this extended surface, this necessary diffusion was the 
main condition which required attention, and not that of temperature. 
Mr. Williams then exhibited the diagram of a boiler to be constructed 
on the above principles, and stated that he had an experimental boiler 
at work, which fully proved the accuracy of the principle. 
Experimental Inquiry into the Strength of Iron with respect to its Ap- 
plication as a substitute for Wood in Ship-building. By Mr.¥ atr- 
BAIRN. 
The number of vessels which of late years have been made entirely 
of iron, and the probability of the greatly extended use of this metal in 
ship-building, render it desirable to attain additional knowledge to 
that we possess upon its resistance to the strains to which it is sub- 
jected in this new application to the purposes above stated. ‘To meet 
the requirements for this purpose, the following series of experiments 
have been undertaken, and in a great measure completed :—Ist. A se- 
ries of experiments on the strength of plates of iron, as regards a direct 
tensile strain, both in direction of the fibre and across it. 2nd. On the 
strength of the joints in plates riveted together, and on the best modes 
of riveting. 3rd. On the strength of the various forms of ribs or frames 
used in ship-building, whether wholly composed of iron or of iron and 
wood. 4th. On the resistance of plates to compression and concussion, 
and on the power necessary to burst them. The experiments have 
been superintended by Mr. Hodgkinson, to whom Mr. Fairbairn ac- 
knowledges himself indebted for many of the results in this research. 
On Strength of Iron Plates-——In the experiments all the plates were 
of uniform thickness; their ends had plates riveted to them on both 
sides, with holes bored through them perpendicular to the plate, in 
order that they might be connected by both, with shackles to tear them 
asunder in the middle, which was made narrower than the rest for that 
purpose. The results were as follows : 
Mean breaking weights in tons per square inch, when drawn in the 
direction of the fibre :— 
Tons. 
Yorkshire plates ... 25°77 ) 
Ditto ditto ... 22°76 
Derbyshire ditto ... 21°68 -Mean 22-52 tons. 
Shropshire ditto ... 22°83 
Staffordshire ditto ... 19°56 
Mean breaking weights in tons per square inch, when drawn across 
the fibre :-— 
Yorkshire plates ... 27°49 
Ditto ditto ... 26°04 
Derbyshire ditto ... 18°65 -Mean 23:04 tons. 
Shropshire ditto ... 22°00 
Staffordshire ditto ... 21°01 
