850 Literary and Philosophical Intelligence. [Oct. f , 



visible ; and made repeated trials on each ciimnlate in the mine. Within the 



species of liglit 



The lijiiit of the miner's candle was 



That of a lamp fnrnished with a tin 



plate retlecior for diminishing tlie 



circulation of the air, and facing 



a blower, v.as . 

 That of a sin!;le connnon lamp 

 Tliat of a double copper wire lamp 

 That of tlie steel mill, very unequal 



and uncertain, but, at its greatest 



intensity of light 



45.5 



49. 



25. 



25. 



body of the mine itself, holes are cntof 

 different diameters, entering into this 

 gas course from the higher parts or roof 

 of tiie mine. Between this gas course 

 and the lower part of the up-cast sliaft 

 of the mine, a communication is made, 

 and the gas by its levity naturally as- 

 cends, though heat is occasionally ap- 

 plied at the lower part of this shaft to 

 accelerate the exit of the gas. Mr. 



It may be pr'oper to observe, without Ryan has introduced his discovery with 

 reference to the superiority of light, that the happiest results into some of th» 

 coals may be worked nearly twice as niost destructive coal-miues in Stafford- 

 cheap by the wire-gauze safe-lamp as by ^hire and Worcestershire, and has ob- 

 the steel mill. tained certificates from numerous re- 



The pleasure of seeing the wire-gauze 



eafe-lamps in general use amongst the mi- 

 ners, and adding to tlie security and happi- 

 ness of this useful class of men, amply re- 

 pays me for the labour ot^ twelve months, 

 devoted to their cause, and for the anxiety 

 which I have often experienced during 

 the progress of the investigation. 

 Newcastle ; Sipt. 9, 181 6. H. Davy. 



P.S. Tlie flame of the tire-damp, &c.— 

 I have shewn, in a paper printed in the 

 Transactions of the Royal Society, that 



spectablc mine-owners. 



]\Ir. Ryan has in the press, a Trea- 

 tise on Mining and Ventilation, em- 

 bracing in a particular manner the sub- 

 ject of the coal stratification of Great 

 Britain and Ireland; with liic most ap- 

 proved methods of discovering, work- 

 ing, and ventilating the same. 



In our last number we drew up, for 

 the information of our readers, a brief 

 abstract of the suppressed vohime of' the 



Uie power of heated wire gauze, to permit Board of Agriculture, of which we had 



the passage of the flame of coal-gas, is di 

 rectly as the size of the apertines, and to a 

 certa'in extent, as the velocity of the cur- 

 rent; I say to a certain extent, because, 

 J)y a'cnrrent of a certain velocity, flame is 

 extinguished. A very slight motion will 

 pass the flame of coal-gas through wire- 

 gauze, having less than 400 apertures to 



obtained a short inspection, and the ar- 

 ticle excited that general interest on 

 w hicli we calculated. We have now the 

 satisfaction to observe that tlie world is 

 put into possession of the entire volume, 

 througii the public spirit of J\Ir. Cle- 

 ment, of the Strand ; and it no doubt 



the square inch, even when it is heated to w ill acquire increased notice from the 

 dull redness; but a very strong current, injudicious measures .adopted to slifle 

 and an ignition above redness, visible in (he important information v/hich it con- 



day-light, is required to pass the same 

 flame through wire-gauze having above 

 700 apertures to the square inch ; and I 

 have never been able to pass the flame of 

 coal-gas, or any carbonaceous flame, 

 through wire-gauze having more than 

 1600 apertures to the square inch, by any 

 means. 



The experiments above detailed on the 

 blower are the first I have made upon 



tains. Viewing tiic publication as a 

 consequence of onr notice of its sup- 

 pression, wo feel that we thereby ren- 

 dered an important service to the 

 nation. 



LoKD Byron having completed a 

 second part of Ckilde Harold, it will h* 

 published with all convenient speed. 



The third volume of the Geological 

 Transactions will ajipcar early in the 



currents offire-damf. They prove what I 

 had inferred from its other properties, and present month, 

 they offer simple means of rendering In the press, and speedily will be 

 ■wire-gauze lamps perfectly safe against all published, a volume of Odes and other 

 ciicumstances, however extraordinary and Poems, by Mr. Henry Neele, of Ken- 

 unexpected, and of placing their security ^,gi, Town, who has occasionally rontri- 

 above the possibility oUoubt ar civil. hx\ie(l, in poetry and prose, to this Ma« 



On this subject w;q have already no- o-a^ine 



ticed the reward bestowed on Mr. " We are extremely concerned to hear. 



Ryan, by the Society of Arts, for a 

 tnodc of ventilating coal-mines. Mr. 

 Ryan's first operation is to insulate (he 

 whole mine, or field, by cutting round 

 it a course or passage, called his gas- 



that the proposed public testimonial of 

 tlie eminent services of Sir John Sin.. 

 CLAIR, (and in aid of which, we believe, 

 letters continue to be received by Mr. 

 Farey, author of the Derbyshire Re- 



poursc ; of a size sufficient to carry off ^^^^ j^^ 37^ Howland-stroct, Fhzroy 

 ^ the gas which would otherwise ac- g,j„are,) has so far failed of removing 



&veii 



