Gartsherrie Coal Cutting Machine
Developed by William Baird and Co c.1862, and used at Gartsherrie Colliery from 1873.
Powered by compressed air, and running on rails.
Described and illustrated in the Engineer in 1874 [1]. The illustration differs from the model, having a single cylinder and incorptating a capstan. Extract of text:-
'With referenece to the Gartsherrie machine, I speak the candid opinion of many practical men, and without any conscious partiality, when I say that it is the most perfect that has yet been devised. For the six oe seven years the Messrs. Baird have carried out successive improvements on this machine, at a large expenditure of labour and money. Until last year it was used only in the collieries belonging to the Gartsherrie firm, where it regulary cout from 300ft. to 350ft. per shift ot eight hours, representing a yield of 75 tons of coal. The first of these machines introduced into England found its way to the Hetton Colliery, where it has now been at work for nearly twelve months. Of its operation at Hetton I am in a position to give you some accurate data obtained over a long course of oxperiments, although not under the most favourable circumstances. Let me say here, for the sake of conciseness, that the principal advntages claimed for the Gartsherrie machine are (1) A diminished cost of production; (2) an improved ventilation; (3) a reduction of waste ; and (4) a relief to the miner from the hardest part of his toil. .....'.The author (J. S. Jeans) makes the important observation that the air exhausting from the machine's cylinders has a double benefit - ventilation and cooling (since the temperture drops as the exhausting air expands).