A USEFUL INVENTION.

Evening Star, Issue 3154, 29 March 1873, Page 2

A USEFUL INVENTION.

Mr J, W. Read, an officer of the Sydney Supreme Court, being impressed with the frecjucnfc and fearful loss of life at sea, bethought him how such disasters might be lessened or avoided. After turning the problem a good many ways, it struck him at last that a self-act-ing signal from the compartment of the ship originating the fire to the captain s cabin was the thing wanted. It was apparent, too, that this signal should indicate any gradual or sudden rise in temperature in the ship s hold, and for this purpose what was needed was a heat meter or thermometer. It occurred to the inventor that air, freely expanding and contracting, and possessing the almost susceptibility to heat and cold, was the best medium to be employed, and then followed the devising of the means by which the atmosphere could be made to perform this service for the captain of a vessel in an entirely reliable manner. After the usual amount of experimenting, the materials for the desired effect were selected —glass, indiarubber tubing, and sulphuric acid. The tubing is to contain the air ; the sulphuric acid is the index or telltale within the meter, and the glass is to allow of the exposure of a portion of the enclosed air to the influence of the atmosphere surrounding it, wherever it may be required. These materials, when available for use, take the following form The meter, which is fixed in the captain’s cabin, resembles a thermometer. Instead of being filled with mercury, sulphuric acid is employed, and this because of its nonevaporative tendency, the tube of the index being exposed to the air enclosed within the indiarubber. The tube containing the acid is bent upwards from the bottom, and thus possesses a short and a long leg. I rom the short leg proceeds the main rubber tube to that part of the vessel where it may be wanted, and at the end is affixed a bulb of fine glass, so placed as to be out of harm’s way, and yet cognisant of those unseen variations of temperature which occur from many causes in the hold of a ship. The elastic tube is thick, with a very fine bore ; and should not this be sufficient to protect the inner vehicle from external influences that would interfere with the conveyance of the silent message from the endangered chamber, the rubber is isolated by a substantial coat of gutta-percha. These are the simple features of the apparatus by which Mr Read proposes to supply the captain with a never failing thermal record of every compartment of his vessel. It is procurable for a few shillings, it is easy to adjust, and should it in practice prove as useful aa it appears in theory, no ship will be allowed to put to sea without one of these admirable instruments. To one unaccustomed to notice the behaviour of atmospheric air when exposed to heat and cold, the instantaneous registration at one end of a long line of tubing of an effect exerted at the other would be a matter of great surprise. A warm breath upon the bulb at one end of one or two hundred feet ot tubing is signalled by the index within a few seconds of time. Within eight seconds of the grasping of the bulb glass by the hand, the liquid in the meter rises several degrees. The atmospheric disturbance produced by the momentary placing ofji lighted match beneath the bulb, is communicated to head-quarters with promptitude and precision. It is not necessary that one of these instruments should be employed to indicate the temperature of each compartment of the hold. Branches may proceed from the main tube, communication being opened or closed with each at will. In order to render the air within the tube insensible to the atmospheric state of any chamber through which it may pass, should the guttapercha isolation prove unsatisfactory, another method has been devised. Two tubes travel together from the sensitive bulb, one communicating with one of the legs of the bent theitnometer, one with the other. SupiKtsing, therefore, the temperature of an intervening chamber to be 212 J , the sulphuric acid in each leg will bo balanced, and the apparatus will give no note of a state of things beyond its own domain. So far, then, as the problem before the inventor was concerned, the instrument we have described is a perfect, cheap, and convenient solution. We understand that ship-owners and merchants and the masters of vessels look with favor on Mr Read’s invention. Should their anticipations prove correct, the effect will be to reduce the rates of insurance, the insurance companies stipulating, of course, that this instrument shall be carried by every vessel. Sydney Morning Herald.