1851 Great Exhibition: Official Catalogue: Class VIII.: Esdaile and Margrave
126. ESDAILE and MARGRAVE, City Saw Mills, Regent's Canal — Manufacturers. BOTHWAY, J., R.N.— Inventor.
The 20-inch cat and general purpose block, which had its strength proved by the testing-machine in H.M.'s dockyard, at Devonport, Oct., 1848, and bore the strain of 50.5 tons (unhurt), its weight only 2cwt. lqr. 0lb.
Two models of mast and yards made to scale; one rigged with the old rope-strapped blocks etc., the other with the inventor's internal-strapped blocks, to show the contrast and the superior qualities to all others.
Two models of cat-heads, with the old iron-bound cat- block and inventor's of reduced size, with weights to prove the difference in their comparative power, with a variety of blocks (from two sheaves in the pair up to fifteen).
Models and drawings of lower yards fitted with inventor's slings and portable gear-blocks, which have been so successfully used in the largest ships in H.M.'s Navy so many years — and other inventions.