l82o.j Sir H. Davy on'-i he Stq^ety Lamp. 455 



ivith fjiTse ,n,o^iojis,,a»4 s^U f^^ es^timates of their oifv^i^yppos^^ 

 po.wers and! acquirements. - on- 'i/j > 



^!; These remarks are but too applicable, to^ ttie, ^ase before ^1^3., 

 AlrtKe world ha^ heard of Sir Humphry Bavy's Safety; -tafWp^ 

 but ho>7 jnany of its membei:s are acquainted with the pppciples 

 CO. whiph'it is founded? Here the ignorance is not rtie^ely S^bsur^;, 

 But'dangerou?; .fqr'a want <>f that knowleclge' ^s le^ 111^^1119,1^!^ 

 casesj an^probatiy will lead in many mbreyto pohs^quenci* 

 (Jisastrous aijid deplorable in the extreme. We have; puf s,elve^ 

 noticed in ©uc walks about this great to \v^,i round wip.ff^gfs,^,^ 

 many of the shop windows, niiscalled safety Ianthpras^,^v^e 

 m^^hes of which are so large that a candle in a yvijre mous,e-;^rap 

 WQulU the as good a security against accident, ih .a^i je^plpsiyg 

 aijMOsphere as' one of those precious safeguards; ahxj yet' real 

 s_a|iBty Tamps may be" purchased both at Newman'sj f n Xisle-stre^^ 

 s^hd of many other philosophical iustrument makers ;: apd ,evefl| 

 t^e fabricators theoaiselves of the culpable suhstitutes j5(e\|iaye 

 mentioned, inight learn to make them properly, if they w.ouli^ 

 only ta^e the trouble to read the invaluable little yolutnebefqre 

 u^,^ , ,|*erhaps they are, not aware of its existence---,it ^hs^l^-,^^ 

 bVWr fault, at all events, if jthey continue in their ignorance^ 



J Tl^e, work, begins by . some gpneral views of the author's prpr 

 ^ep'i,^.his,researches on ,t|xe safety lamp> and' of the principle^ 

 on which its seourity depends; ; aJ^d this section we most e^pe^ 

 cmjiy recommend t-o the Cfireful peru^^l, pf the wire-wqrke~^^ 

 a^V^^aid.- ^1".% pfi^^^^^ W, pearly explaJii^d, j^^t tH^;^ 



cannot iriisundefsland thern, and if they wilfully hereafter negrj 

 le,9t tjiem,.they, are answerable for. all the dreadful consequenceB 

 t^ejr jtHattention and. folly may give rise to.. We trust tnat the 

 manufactiirers of the lamps Tor the coal mines are not liable to 

 the preceding ; censure ; but .even in the cellars' of this gasi* 

 lighted metrppblisj some serious accidents have happened, anq 

 theii; frequency may be much augmented if persons enter them 

 in unguarded confidence in the false security of one of the lan- 

 thorii^ we have mentioned. That the said wire-workers may 

 have still less ground to plead ignorance of the principle of the 

 regJi safety lamp^_ we shall quote the i^otst iffiporUnt.pja^^g^j Qi^ 

 the^, subject in pur author's own words. ,■.,!;■ ^ ; -: • -vv-dt 



jl Sir Humphry Davy began his experiments by a cTiemical 

 ejcamination of the substance with which he had to contend-;-^ 

 the, fire-damp of the coal mines. He found that it requires very 

 large quantities, of atmospheric air to produce an explosive mix,^ 

 ture ; namely, about seven or eight times its volume of air, in 

 which proportion it explodes with most energy — with between 

 fiv^e ^aiid, ,slx yolupies it explodes feebly ; and it retains its expl9rj 

 sly.e ppWer,,'>vh5i^,^|^ pi-9portip'^^^^^ of ^a^.^ (pttFrd 



He 'fofind tne nre-d; 



e fire-damp mufch less combustible than other 



