CHAPTER V. 



THE LIME-LIGHT AND ITS MANAGEMENT. 



[HE lime-light was discovered about the year 1826 

 by Lieut. Drummond, R.E., during the progress 

 of the Ordnance of Ireland Survey, when the 

 want of some method of signalling between distant stations 

 was much felt. As originally constructed, Drummond's 

 lamp was very different to the convenient forms of lime jet 

 now in use. It consisted of a blow-pipe, which impinged 

 upon a ball of lime about as big as a marble. This lime 

 ball did not last more than half an hour, but when spent 

 another took its place automatically. The lime ball was 

 placed in the focus of a parabolic silvered-copper reflector. 

 With this apparatus, the light was visible from Antrim in 

 Ireland, to Ben Lomond in Scotland, a distance of ninety- 

 five miles as the crow flies. Upon another occasion, the 

 light from the Drummond lamp was distinguishable at a 

 distance of one hundred and twelve miles. 



When manufactured limes cannot be obtained, a piece 

 of limestone fresh from the kiln can be sawn roughly to 



