W 1 R 



W 1 11 



Marcrt : — A piece of wire, about fix inclies lonor, having 

 been bent to an angle in the middle, one half ol its length 

 was held in the flame of a fpiritlamp impelled by a current 

 of oxygen, and its extremity was thus fufed in about half a 

 minute. An inch of the wire above-mentioned duly coated 

 with filver was drawn, till its length was extended to 

 182 inches ; confequently the proportional diminution of 

 the diameter of the platina will be exprefled by the 

 fquare root of 182, fo that its meafure had become 



The fpecific gravity of the coated 



253 X '3-5 3425 



wire was affumed to be 10.5, and ITnce the weight of 100 



inches was 1 14 grains, its diameter was inferred to be 



— - of an inch, and juR eighty times of the platina thus 

 ^2>8 



contained in it. With portions of the platina wire thus 

 obtained, and fuccefllvely reduced in diameter, its tenacity 

 was afcertained ; and the refults of feveral trials (hewed in 

 general, that the procefs of wire-drawing, which is known 

 to improve the ftrength of metals within moderate limits, 

 continued alfo to add fomething to the tenacity of platina, 



fven as far as — of an inch, which fupported i\ grain 



18.000 '^'^ ^ 



:>efore it broke ; but the wire in which the experiments 

 i\'ere made began then to be impaired by repetition of the 

 operation ; fo that although he afterwards obtained portions 



af it as fmall as 



of an inch in diameter, it was in 



30.000 



many places interrupted, and he could not rely on any trials 

 if its tenacity. For other particulars with regard to thefe 

 line wires, we refer to the Phil. Tranf. vol. ciii. pt. i. 



Wire, Silver, is the fame with gold wire, except that 

 the latter is gilt, or covered with gold, and the other is not. 

 There are alfo counterfeit gold and filver wires : the firft 

 made of a cylinder of copper, filvered over, then co- 

 rered with gold ; and the fecond of a like cylinder of 

 :opper filvered over, and drawn through the iron, after 

 :he fame manner as gold and filver wire. 



By 43 Geo. III. c. 68. feveral duties are impofed on 

 ivire imported, as fet forth in tables annexed to the aft ; 

 md by c. 69. fched. A. duties are laid upon wire made in 

 Great Britain ; and by 49 Geo. III. c. 98. new duties are 

 impofed. Every wire-drawer who (hall draw any gilt or 

 filver wire, commonly called ' big wire,' (hall take out a 

 licence, for which he (hall pay 2/., to be renewed aimually on 

 pain of 20/. 24 Geo. III. c. 41. One licence fuffices for a 

 partnef(hip. Notice is to be given of working on pain of 

 20/., and the place of working is to be approved by the 

 commifTioners under the fame penalty. Wire, and bars for 

 making it, and utenfils, found in any private workhoufe, of 

 which no notice hath been given, (hall be forfeited. 

 Officers (hall be permitted to enter and furvey, and the 

 penalty of obftrufting him is 20/. 10 Ann. c. 26. Pre- 

 venting him from taking a juft account incurs a forfeiture 

 of 100/. 26 Geo. III. c. 77. Juft fcales and weights (hall 

 be kept on pain of 10/. Perfons ufing falfe fcalcs and 

 weights forfeit 100/. 10 Geo. III. c. 44. And the fame 

 (hall be forfeited and feized. 28 Geo. III. c. 37. Ingots 

 or bars of filver, defigned for gilt wire, (hall be weighed 

 m the prefence of the excife officer, before they be covered 

 with gold, and again weighed and marked after the gold is 

 laid on, under penalty of 2c/. 15 Geo. II. c. 20. 



By lo Ann. c. 26. an allowance of one-fifth is made 



for wafte in reducing the big wire to fmall wi;e. Removing 

 wire before it is furveyed incurs a penalty of 40/. ; and 

 unfurveyed wire is to be kept feparate,on pain of 10/. ; and 

 the puniihment of conceahng wire, &c. is a forfeiture of 20/. 

 The wire made (hall be entered every month, on oath, on 

 pain of 100/. The duty muft be cleared off in fix weeks 

 after entry, on pain of double duty. 



By 15 Geo. II. c. 20. and 22 Geo. II. c. 36. no 

 foreign embroidery, or gold or filver brocade, thread, lace, 

 fringe, or work made thereof, or of copper, brafs, or 

 other inferior metal, or gold or filver wire, or plate, (hall 

 be imported. And by 10 Ann. c. 26. if any perfon 

 (hall export any gold or filver thread, or lace or fringe 

 made of plate wire fpun upon filk, he (hall have a draw- 

 back after the rate of ^s. a pound avoirdupois, of fuch 

 filver thread, lace, or fringe, and of 6s. SJ. a pound of 

 fuch gold thread, lace, or fringe. 



For regulations concerning the true making of gilt and 

 filver wire, fee the llatute 15 Geo. II. c. 20. and for pro- 

 hibiting the felling or working up of foreign gold or filver 

 lace or thread, fee 22 Geo. II. c. 36. 



Wire, Brafs, is drawn after the fame manner as the for- 

 mer. Of this there are divers fizes, fuited to the divers 

 kinds of works. The lineft is ufed for the ftrings 

 of mufical inftruments, as fpinete, harpfichords, mani- 

 chords, &c. 



The pin-makers likewife ufe vaft quantities of wire of 

 feveral fizes, to make their pins of. See Pjn. 



Wire, Iron. See WiRv^fupra. 



WiRE-Gauze Safety-Lamp, and Safety-Lamp, in the virts, 

 are lamps conftrufted to prevent the explofion of inflam- 

 mable air in mines, by intercepting the communication of 

 the flame on the infide of the lamp with the furrounding 

 atmofphere. The difcovery of fafety-lamps for this pur- 

 pofe belongs exclufively to our own country, and will form 

 a new era in mining operations. We fliall, therefore, ftate 

 the hiftory of their invention with as much accuracy as pof- 

 fible, amidft the contending claims of the different inventors 

 for priority. The explofions of inflammable air in coal- 

 mines arife from the ignition of carburetted hydrogen evolved 

 from the ftrata, and mixed with the atmofpheric air that 

 circulates through the mine. Thefe explofions very fre- 

 quently occafion the moft fatal efFedts, deltroying the hves 

 of all the perfons employed as well as of the horfes, and 

 producing great mifchief to the fubterranean works. Some 

 mines are much more liable to accidents from this caufe than 

 others. In fome the carburetted hydrogen accumulates 

 flowly from the want of due circulation ; in other mines, 

 it is generated very rapidly, iifuing from fiifures called 

 blowers, which occur either in the roof, the floor, or the 

 fides of the mine. 



In the coal-fields of the Tyne and the Wear, it has been 

 eftimated that fix hundred men and boys were deftroyed in 

 two years by explofions in the mines ; but thefe accidents, 

 unlefs they took place on a large fcale, were as much as 

 poffible kept from public notice, partly from the fear of 

 alarming the workmen, and partly from the apprehenfion of 

 blame to the viewers and managers of the works. Of thefe 

 melancholy cataftrophes, few regifters are kept in any part 

 of Great Britain ; but in the year 1810 an explofion took 

 place in a mine in the pan(h of Felling near Newcaftle, 

 which, from the magnitude of the evil it occafioned, excited 

 a general fenfation of horror throughout the country. In 

 this mine, the property of v/ealthy and liberal owners, no 

 expence had been fpared in the introduftion of machinery 

 and the moft approved methods of ventilation. ( See Ven- 

 tilation of Mines.) Notwithftaoding this, on the 25th of 



May 



