£$22 SCIENTIFIC NEWS. 



Ccmftruftion of be very nearly in a vertical line : but it may eafily be Imagined 

 a fecret lock ac- t j iat it " vv ;n not ^ e exadly fo, unlefs the ftuds of the bolt mould 

 the proprietor, exactly fill the fpaces, fo as to leave no fhake. The fifth ftar 

 correfponding to the center wheel, is merely ornamental. 



In this difpofition of the lock we may affirm, that it is adjuft- 

 ed to the word A A A A. 



In order to change the fecret, and adjuft the lock to the word 

 long, for example, the firft fcrew-head muft be turned round tor 

 the left, until the letter L of the key coincides with the ftar. 

 In the fame manner the letter O is made to coincide with the 

 ftar of the fecond fcrew-head ; the letter N with that of the 

 third; and that of the letter G with the fourth. The flat wheels 

 remaining in that pofition, the ferrils are then to be difpofed in 

 a right line, and the fecret will confift of the word long. The 

 bolt is then to be put in its place, and the handle turned to ad- 

 vance its flop. 



When the lock is to be fhut, the fcrew-heads muft be dif- 

 pofed fo as to form the word long ; and in this pofition the bolt 

 may be moved backward and forward by turning the middle 

 wheel. If one or more of the fcrew-heads be deranged, the 

 bolt is locked faft. But in order to open it, the fame difpofition 

 muft be made, and the bolt may again be movedj 



We may obferve that, when the fcrew-heads are derange dj» 

 the bolt neverthelels is capable of moving through the fpace of 

 13, arifing from the fize of the ferrils ; which affords an advan- 

 tage for uiing it as a fimple bolt, to be put backwards and for- 

 wards within the chamber. 



(To he concluded.) 



SCIENTIFIC NEWS, &c. 

 Cheap Mttkod of producing Light. 



R. EZEKIEL WALKER informs me that he has difco-v 

 vered a cheap method of producing light, which feems to pof- 

 fefs advantages much fuperior to the common modes of illumi- 

 nation. This light generates no fmoke, and requires not the 

 aid of fnuffers. 



Qb 



