Mr. Fenton, general manager, and Mr. Driscoll, an inspector of the company, having been examined as to the improvements made in the ventilation of the tunnels, and the absence of complaint from _employés_ of the company, or from passengers with respect to the atmosphere, the jury, almost without hesitation, returned a verdict of “Death from natural causes.”
The singular fact was elicited at the inquest that the peculiarly “pungent smell” of the tunnel is due rather to the friction of the brakes, than to any other cause. The partial combustion of the wood produces a pyroligneous carbo-hydrogen, as Dr. Letheby styled it, together with a small amount of sulphurous acid gas. These the nose and lungs will detect sooner than the most delicate chemical tests, and they are the real producers of the coughing and unpleasant feeling experienced by some passengers. Such vapours, however, only affect delicate people. This will account for the fact that people, travelling through ordinary tunnels, are free from irritation and coughing. The Metropolitan Railway is the only tunnel in which, owing to stoppages at intermediate stations, it is necessary to put the brakes on.
The efforts made by the company to ensure the best ventilation and purest atmosphere possible, are unremitting. Before the opening of the line an extended series of experiments was made with various specimens of coke supplied by all the leading coke manufacturers in the kingdom. That which best bore the crucial tests, to which the specimens were submitted, is the coke supplied by Messrs. Straker and Lowe from their Brancepeth Collieries near Durham. Coke for locomotives, and other purposes, is usually burned seventy-two hours. When coke of a very superior quality is required (so that all sulphurous and noxious vapours may, as far as possible, be consumed) it is burned ninety-six hours, but all coke used on the Metropolitan Railway is burned twenty-four hours more—that is 120 hours. Special ovens have been built for burning it, and when the process of combustion is completed, the coke is, what is well known in railway locomotive phraseology, “hand picked.” Thus, only the bright coke of each burning is allowed to be sent to London; any outside or dirty coke, however good it may be in reality, being kept back. It is, therefore, impossible to procure, in the whole range of fuel, any more free from ingredients likely to produce unpleasant smell, or to affect respiration.