§84 Collier or Miner Life Preserver. -^Trigonometrical Survey* 



leading principle of VVoolf's engine? or from improved boilers?-— 

 and if so, in what does the improvement consist ? — or from these 

 and other causes combined ? As particular an answer as possible 

 would at the present moment be peculiarly interestin/r, as it is 

 known that some questions connected with the use of this most 

 powerful ajjent now occupy the attention of a committee of the 

 House of Commons. ^ 



tOLMER OR MINEK LIFE PRESERVER. 



We liave just seen a very curious contrivance by Mr. Geo. Prior', 

 watch-maker of Leeds, (son of Mr, John Prior, the celebrated 

 Yorkshire mechanic,) which may be considered as a Collier or 

 Miner Life Preserver, and which comjjincs the two advantages 

 of simplicity and efficacy. Tiie ol)ject of this invention is, to pre- 

 vent those accidents which are so frequently occurring from the 

 breaking of the ropes by which corves or buckets are let into the 

 coal-pits or mines. To effect this purpose, iron pins are intro- 

 duced into the tipright frame on v.liich the corfe slides. The 

 apparatus to which the corfe is fixed is furnished with a power- 

 ful spring catch on each side, which, without causing any friction 

 in the ordinary working of the corfe, opens out the moment the 

 rope breaks, and, fixing itself on the iron pins, causes the corfe 

 to be suspended, and prevents the person in it from being preci- 

 pitated to the bottom of the pit. This apparatus, which is 

 adapted to the machinery now in use by the miners, adds very 

 little weight to the corfe, and may be fitted up at a trifling ex- 

 pense. — Leeds paper. 



TRiGONOMETRICAL SURVEY. 



M. Biot, of the French Institute, well known by his curious re- 

 searches relative to the polarization of light, has come to this country 

 for the purpose of accompanying Colonel Mudge, the conductor of 

 the Trigonometrical Survey, on a philosophical expedition to the 

 Orkneys. M. Biot is now making experiments on the length of 

 the seconds pendulum, at Edinburgh ; while Colonel Nludge, 

 and his able assistant Captain Coll)y, are measuring a base of 

 verification near Aberdeen. The several operations at Edinburgh 

 and Aberdeen ari; expected to be terminated about the middle 

 of June ; when, it is understood, the party will be joined by Dr. 

 Gregory, of the Royal Military Academy, Woolwich, and the 

 whole proceed to the Orkneys, for the purpose of carrying on 

 simultaneously the requisite astronomical observations connected 

 with the Trigonometrical Survey, and the experiments that re- 

 late to the vibrations of pendulums. These joint processes, con- 

 ducted at so high a latitude, may be expected to throw consider- 

 able light upon that curious class of problems which regard the 

 figure of the earth. African 



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