ORIGIN OF USEFUL INVENTIONS. 



8] 



lafely-lamp, invented by that accomplished chy- 

 mist, the late Sir Humphrey Davy. He insti 

 tuted a series of philosophical experiments, with 

 the express purpose of constructing, if possible, 

 a lamp by which the miner might walk through 

 a body of fire-damp in his subterraneous apart 

 ments without danger of an explosion; and the 

 success with which his investigations were at 

 tended, led to one of the most beautiful and use 

 ful inventions which distinguish the period in 

 which we live.* Had this ingenious philosp- 

 pher been ignorant of the nature and properties of 

 carburretted hydrogen gas, of the composition of 

 atmospheric air, of the nature of combustion, and 

 of the general principles of chymical science, 

 he could never have hit upon the construction 

 of this admirable instrument, and the useful mi 

 ner would still have been left to grapple with his 

 invisible enemy (the fire-damp) without any 

 means of escaping from its destructive agency. f 



See Appendix, No. IX. 



* It is more than probable, that fatal accidents 

 have occurred in coal mines where these lamps have 

 been used, owing to the ignorance and inattention 

 of some of those artists who have been employed in 

 forming the wire- gauze, with which they are sur 

 rounded. A friend of mine, who performed a great 

 variety of experiments with this instrument, with 

 every combination of explosive gas, informed me, 

 that, with a lamp surrounded with wire-gauze, ma 

 nufactured by an artist in a town in the north of 

 England, and whn supplied it for the use of the, mi 

 nersan explosion uniformly took place when the 

 instrument was placed in a body of inflammable 

 gas. He suspected that the apertures in the wire- 

 gauze were too large, and remonstrated with the 

 artist on his want of accuracy ; and it was not be 

 fore he procured gauze with smaller apertures that 

 his experiments succeeded ; and they were attended 

 with complete success in every future experiment, 

 after the gauze was changed. So small was the dif 

 ference in the contexture of the two pieces of the 

 gauze, that, to a common eye, it was scarcely per 

 ceptible. It is found by experiment, that the aper 

 tures in the gauze should not exceed one twentieth 

 of an inch square, and that wire from one fortieth 

 to one sixtieth of an inch diameter, is the most con 

 venient. Had the artist alluded to, known how to 

 perform experiments with this instrument, and tried 

 the effects of his gauze before he sold it for the pur 

 pose intended, such serious blunders would not 

 have been committed. Who knows but the defi 

 ciency in the gauze alluded to might have been the 

 cause of the destruction of several lives in the pits 

 where it was used ? for it is a certain fact that acci 

 dents from explosions are occasionally recurring, 

 oven in mines where these lamps are generally in 

 use. Hence the necessity of chymical knowledge 

 and attention to scientific accuracy in those who are 

 the manufacturers of instruments of this descrip 

 tionon the accurate construction of which the 

 lives and comforts of a useful body of the commu 

 nity may depend. I know not whether it be custo 

 mary to put the safety-lamp into the hands of the 

 minor, without first trying its efficiency for resisting 

 thy effects of explosive gases. If it is not, it is a 

 most glaring and dangerous oversight; and there 

 can be no question, that to the neglect of this pre 

 caution are to be attributed many of those explo 

 sions which have taken place in the mines where 

 this lamp has been introduced. Besides, such ne 

 glects have a direct tendency to detract from the 

 merits of this noble invention, to prevent its univer 

 sal adoption, and to render uncertain its efficiency 

 fnr warding off destructive explosions. But from 

 ttie experiments alluded to above, which were per- 



We may farther remark, that the mechanic 

 whose mind is enlightened with scientific know, 

 ledge, has a much greater chance of being instru* 

 mental in improving the arts, than the mere chy- 

 mist or philosopher. While the mere philoso 

 pher is demonstrating principles and forming 

 theories in his closet, and sometimes performing 

 experiments, only on a small scale, the work 

 man, in certain manufactories, has a daily op 

 portunity of contemplating chymical processes 

 and mechanical operations on an extensive scale, 

 and of perceiving numberless modifications and 

 contrivances, which require to be attended to, 

 of which the mere scientific speculator can form 

 but a very faint and inadequate conception. 

 Being familiar with the most minute details of 

 every process and operation, he can perceive 

 redundancies and defects imperceptible to other 

 observers ; and, if he has an accurate knowledge 

 of the general principles on which his operations 

 depend, he must be best qualified for suggesting 

 and contriving the requisite improvements. As 

 the mechanic is constantly handling the tools 

 and materials with which new experiments and 

 improvements may be made, observing the ef 

 fects of certain contrivances, and of deviations 

 from established practice and witnessing the 

 chymical and mechanical actions of bodies on 

 each other he has more opportunities of obser 

 vation in these respects, and, consequently, is 

 more likely than any other class of society to 

 strike out a new path which may lead to some 

 useful invention in the arts, or discovery in the 

 sciences.* But if his mind is not imbued with 

 knowledge, he trudges on, like a mill-horse, in 

 the same beaten track, and may overlook a thou 

 sand opportunities of performing experiments, 

 and a thousand circumstances which might 

 suggest new improvements. 



In short, in so far as chance is concerned in 

 new discoveries and improvements in the arts, 

 the scientific mechanic has a hundred chances 

 to one, compared with the ignorant artificer, that, 

 in the course of his operations, he shall hit upon 

 a new principle of improvement : his chances 

 of such results are even superior to those of the 

 most profound philosophers who never engage in 



formed with the greatest care, and with every pos 

 sible combination of explosive gas, and frequently 

 exhibited in private, and before large public audi 

 encesthe efficiency of this lamp for resisting the ef 

 fects of fire-damp is put beyond the shadow of a 

 doubt. It is known to be the practice of some mi 

 ners, occasionally to screw off the top of their lamp, 

 in order to enjoy the benefit of more light than what 

 shines through the wire-gauze. Such a practice 

 ought to be strictly prohibited, and the instrument, 

 if possible, rendered incapable of being opened at 

 top a practice which may probably have been the 

 occasion of several explosions. If the workmen 

 in mines were carefully instructed in the general 

 principles of chymistry, and particularly in the na 

 ture of combustion, explosions, and the qualities of 

 the different gases, they would not dare to hazard 

 such dangerous experiments. 



See Appendix No. X 



