The Margherita Cave received its name in honour of the wife of Lieut.-Colonel Cracknell, Superintendent of Telegraphs. Col. Cracknell visited the caves in 1880, and on the 22nd July illuminated this and some other portions with the electric light. The Margherita was the first of the underground chambers in which flashed its brilliant rays.
In the absence of facilities for generating electricity by means of the now well-known dynamo machine, Colonel Cracknell had recourse to primary batteries, and adopted the form known as the Maynooth or Callan cell, the elements of which were cast iron and zinc in solutions of nitric and sulphuric acid.
It was not an easy task to unload and carry up the iron cell battery and the apparatus into the cave, as each set of six cells weighed 96 lbs. The whole, together with the acids and the electric light apparatus, exceeded 15 cwts. The battery, however, was soon made ready, and to the admiration of all present Cave Margherita was illuminated by the electric light. A photographic apparatus was then placed in position, the plates were exposed, and in 15 minutes the first negatives were produced, and said to be all that could be desired.
It is satisfactory to learn that arrangements are almost complete for the permanent lighting of the caves by electricity. Lieutenant-Colonel Cracknell proposes to illuminate them in sections, containing each, say, 25 incandescent lamps, and when one section has been thoroughly explored the lamps therein will be cut off and those in the next section brought into operation, and so on until the whole of the interior has been examined. It is intended that Swan's incandescent lamp of 20-candle power shall be used.
The electricity is to be generated by a small Edison dynamo, with which accumulators of the Elwell-Parker type will be kept charged, so that at all times there will be a supply available for lighting the lamps. It has not yet been determined whether to use steam or water power, but it is thought likely that sufficient of the latter may be secured in the vicinity of the caves to work a turbine, and thus produce the necessary energy.
