OX THE EXFLOSIBILIT'E OF COAL OILS. 109 



over the surface of the calico, and it was readily extinguishable by the 

 breath when first kindled. Although a single calico dress may of itself 

 be deemed dangerously inflammable, yet it requires more time to 

 become ignited whilst wet with kerosene oil, but the intensity of the 

 flame becomes finally much greater. 



When a similar experiment was repeated on cotton cloth moistened 

 with burning fluid, camphine, and spirits of wine, the blaze spread 

 instantaneously over the surface of the cloth with terrific violence, 

 affording ample reason for the belief of an increased hazard in using 

 them in lamps even for household illumination ; and yet how few are 

 the disastrous accidents which have occurred from this cause, in 

 comparison of the vast number of cases where lamps supplied with 

 these inflammable liquids have been harmlessly used with ordinary 

 care. 



. An important incidental security, resulting from the use of kerosene 

 in lamps, is an exemption from the crusts of coal which are found to 

 collect on the wicks where whale oil is burnt, and which not only 

 obscure the radiance of light, but frequently sparkle off upon adjacent 

 combustible bodies. It is necessary often to trim the wicks of whale 

 oil lamps, which in manufactories is frequently done by workmen im- 

 patient at the waning glimmer. The burning crusts of the wick, 

 knocked off without regard to surrounding combustible matter in 

 cotton mills, has often set them on fire and burned them. Turpentine 

 is also used for lighting the wicks of such lamps, which increases 

 the danger in cotton mills. For these reasons it is believed that the 

 comparative hazard from fire by the use of whale oil in lamps in cotton 

 mills, is greater than where coal oil is similarly used, of the quality 

 before stated. 



Although pure sperm oil may be free from the preceding objection, 

 yet, so great is the temptation of a profit of about one dollar per gallon 

 from mixing the cheaper whale oil with sperm oil, that it has become 

 nearly impracticable to obtain a sufficient supply of the latter, even for 

 oiling machinery. So great, indeed, has been found the difficulty of 

 procuring pure sperm oil in England for this purpose, that the heavier 

 coal oil has been there successfully substituted in place of it for this 

 special purpose. 



Ample capital and skill have recently been applied to the new 

 branch of business of the distillation of coal oils, and no deficiency 

 of an abundant future supply will hereafter occur for purposes of 

 illumination, or, when properly prepared, for lubrication of ma- 

 chinery. It appears that an entire cargo of coal oil has recently been 

 exported to Italy. The supply of coal oil will not fail until the 

 supply of coal in the depths of the earth becomes exhausted. How 

 long this may continue has already become a curious subject of calcu- 

 lation. 



The consumption of coal for purposes of navigation, and for motive 

 power in the useful arts, is manifestly destined to go on, increasing with 



