On preventing^ the Freezing of IVater in Pipes. 209 



the erand trigonometrical survey^, on the top of Quainton- 

 hill,^near A\-lesbury; and being surprised, while there, by 

 a considerable explosion, I hastened to a pit, near where 

 some workmen had just blasted a large piece of rock into 

 fragments. On inquiring their process, they assured me they 

 used no gun-powder, but simply undermined the rock for 

 about a yard in length, and half a yard in depth, and intro- 

 duced a small faggot of brush-wood, furze, or a bundle of 

 straw, into the cavity, and set it on fire, and that, in a few- 

 seconds, the confined air in the stone blew up with great 

 force. The fragments of the explosion I had heard, were 

 lying about, much the same as they would have been thrown 

 bv a'blast of gunpowder. I saw in the pit several other ex- 

 cavations forming under blocks of two or three feet thick- 

 ness, intended to be blasted up in the same manner: but 

 night was approaching, and I was unable to stop to witness 

 the next explosion, or to collect further particulars 5 which I 

 have many times since regretted. Should this singular 

 mode of blasting be practised in other places within the 

 knowledge of your correspondents, they will be rendering 

 me and some others a service by communicating the local 

 and other particulars. 



lam, sir, 

 12, Crown-street, Westminster, Your obedient servant, 



Dec. I, 1S04. J. FAREy. 



P. S. Blast-holes are frequently required to be made hori- 

 zontal, or even inclining upwards; in which case dry sand 

 would be inapplicable as a stopper. 



XXXV'II. On preventing the Freezing of IVater in Pipes. 

 By J. T. Barber, Esq. 



To Mr. Tillock. 



Jl he discovery of an effectual means of preventing the 

 freezing up of water-pipes has long been a desideratum in 

 science; but although some methods have been proposed, 

 they have either been so troublesome or expensive, or par- 

 tially applicable, as not to prove calculated for practical use; 

 simplicity and cheapness, l}eing essential to the general in- 

 troduction <jf any contrivance for the above object, must be 

 considered inseparable from the invention that would aim at 

 public utility. In submitting to consideration the follow- 

 ing plan, therefore, I only lay claim to the merit of pointing 

 Vol. £-0. No. 7y. Dec'. 1S04. O out 



