AN AUTOMATIC FIRE ALARM.

Evening Post, Volume LVII, Issue 31, 7 February 1899, Page 5

AN AUTOMATIC FIRE ALARM.

What appears in the model to be an exceedingly ingenious and effective contrivance for the detection of fires, calling out the brigade, alarmjng inmates, and also indicating the exact position of a" fire, its extent and the direction of its spread, is being exhibited at the rooms of the Society of Marine Engineers, Queen's Chambers. The inventor is Mr. Charles May, mechanical electrician in the employ of the Telegraph Department at Dunedin, and his invention may be briefly described as follows : — Along the centre of a room and close to the ceiling, a long prepared wire is carried, having &t its centre a small electric contact point, suspended over a cup which is in connection with an electric magnet and a Morse telegraphic transmitter. So sensitive is the wire that it lengthens instantly on any increase of temperature and closes the contact. The means of adjustment are ample, however, and whilst it can be set fine enough, to operate by a person's breath, it can, on the other hand, be made to require a heightened temperature of 50 or any other number of degrees. This is necessary because there would be fluctuations of heat in living rooms which require to be taken into account. When the system is installed a chart showing the plan of the building, with measurements, is supplied to the Fire Brigade, and a similar one is placed on an indicator board in a prominent window or outside the building. More than one of these indicators can be used, and in the case of a large hotel one with gong attached could be placed in each corridor. What happens, then, when a fire occurs is this. Tho first flush of heat in any part of the room naturally rises to the ceiling and spreads out in all directions. The moment the sensitive wire is .affected contact is completed, the gong Is rung, and on the indicator board a disc is dropped which indicates the exact seat of the trouble, and to the firemen the length of hose required to cope with it, As long as the heat lasted the gong would continue to ring, inmates would run to the nearest indicator board and see at once where the fire was, and if spreading other discs would drop, thus showing the extent of the building affected, and the rate and direction of travel. For cities provided with fire circuit wires and street alarm boxes, such as Dunedin and Ghristchurch, a short connecting wire would be attached to the May transmitter, 'and in this case the city Fire Brigade would receive instant notice, and on their arrival would be shown by the indicator board preoisely the location of the trouble. The advantage of this will be apparent to everyone. The building is probably full of smoke, and instead of groping about to locate the fire or deluging unaffected rooms, the officer in charge is shown that while a certain room No. 7 is afire, which will require so many feet of hose to cope with, the surrounding apartments are not yet affected, and that the upper and lower stories, although emitting smoke, are not yet in danger. The invention, which is known as May 'a Automatic Fire Annunciator, may be applied with equal advantage to a ship, or to freezing works to show a rise in temperature. It has been taken up by a colonial syndicate, and has been exhibited to several members of the Government, members of the Underwriters' Conference Avho have been sitting here, and of the Municipal Fire Brigade, and was seen today by City Councillors. Captain Mitchell, of the Dunedin Fire Brigade, considers that the invention would sound an alarm 13 minutes quicker than any existing automatic alarm in use, which is an important point.