OCTOBER 10, 1845.

On

EXPERIMENT 9.

On a malleable iron beam, of the annexed sectional form, 10 feet 8 inches long, and 10 feet between the supports.

Weight

in lbs.

Dimensions at a=1.000 in. x 23 in.

Dimensions at b 350 in. x 8 in.

=

α

I

Remarks

с

In both these experiments the beams yielded to lateral deflection, showing certain defects of form arising from want of lateral strength and breadth in the top and bottom flanges.

EXPERIMENT 10. OCTOBER 10, 1845.

Malleable iron beam of the same form as the last, 10 feet 7 inches long, and 10 feet between the supports.

Thickness, a=1·000 in. × 2.75 in.

Thickness, b= .380 in. x 8 in.

Thickness, c= ·420 in. × 4·30 in.

Weight of beam=276 lbs.

In these experiments it will be necessary to remark, that they were made with the narrow flange uppermost ; a position rather favourable to the strength than otherwise, on account of the increased area of the top flange, which is equal to 2·75 inches; and the bottom flange is only 1.8 inch, a circumstance (deduced from subsequent experiments) favourable to the resisting powers of a wrought-iron beam.

Manchester: April 10, 1850.

321

APPENDIX II.

Experimental Researches to determine the strength of Locomotive boilers, and the causes which lead to Explosion.

A DIFFERENCE of opinion having arisen between a gentleman high in authority and myself concerning the causes of an accident which took place through the explosion of a locomotive engine at Manchester, on the Eastern Division of the London and North-Western Railway, I deemed it necessary to institute a series of experiments, not for the purpose of confuting the arguments of others or confirming my own, but to determine the real causes of the explosion, and to register the observed facts for our future guidance in guarding against such fearful catastrophes.

After a careful examination of the boiler a few hours subsequent to the explosion, I found one side of the fire-box completely severed from the body of the boiler, the interior copper box forced inwards upon the furnace; and with the exception of the cylindrical shell which covers the tubes, the whole of the engine was a complete wreck, as exhibited in the annexed plate.

Mr. Ramsbottom, the Locomotive Superintendent, in his Report to the Directors, states that 'the engine in question was made by Messrs. Sharp, Roberts, and Co. in the year 1840, has been worked at a pressure of 60 lbs. per square inch, and has run in all a distance of 104,723 miles, a great part of which has been either entirely without load, or nearly so. As the cylinders are only 13-inch diameter, it has been for some time too light to work any of our trains; and has therefore been chiefly employed since 1849 in piloting the trains through Standedge tunnel, along with another engine of the same size, which is now at work.

The fire-box was originally ths of an inch thick, and is now a little over ths of an inch; and, from its excellent condition, might well be supposed (as indeed it was by Mr. Sharp, of the firm of Sharp, Brothers, and Co., who inspected it a few