The Illustrated London News (7 December 1850): 433. Source: An Internet Archive online version of a copy in the University of Michigan Library. Click on image to enlarge it..
Text from The Illustrated London News
In the General View of Works the most prominent feature is the large crane, by which the cast-iron girders are unloaded from the waggon—one of Pickford’s in the present instance. A girder is seen, suspended by the chain, in the act of being moved round to be placed between the jaws of the hydraulic testing machine. In order that the progress of the works might not be impeded, at their commencement it was found absolutely necessary to test the girders by night as well as by day, for which purpose artificial light was required, and the manner in which this is accomplished is shown in the view: — A lamp, with flexible tube, by which the gas is conveyed from the main, is suspended from the jib of the crane, with which it can therefore be moved round in any required direction, and also be raised or lowered according to circumstances. In the foreground is one of the sappers and miners men waiting to test the strength of the girder. We have only to stand by a little while, in order to discover the vigilance exercised by this person in performing his duty; so that, in addition to the respectability and constant supervision of the contractors, the public have this farther assurance of safety. 
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Last modified 21 August 2017