DISCOURSE OF W. B. TAYLOR. 313 



aration in later years by liigli distillation, seemed to justify the 

 attempt. Not only was a laborious inquiry into the best conditions 

 of combustion, by precise photometric measurement required, but 

 for the security of the service, equally laborious examinations into 

 the best practicable methods of testing, of handling, and of storing 

 this material.* To secure a proper oxygenation in burning, a 

 modification of the lamp was required. ''It was soon apparent 

 that the use of mineral oil Avould necessitate a change of lamps, 

 and attention is now directed to the perfection of one Avhicli will 

 produce the best results from this illuminant. It is thought that 

 the lamps now used with lard oil can be converted at no great 

 expense and successfully used with mineral oil. Our experiments 

 have shown that this oil can be more readily used in the smaller 

 lamps; and it is proposed as soon as suitable ones can be prepared, 

 to put it into use at such stations of the fifth and sixth order, as 

 may be thought expedient; when if it be found satisfactory, an 

 attempt will be made to substitute it for lard oil in lamps of the 

 higher orders." f "This change is proposed entirely with reference 

 to economy; for it has been found by rejseated experiment, that 

 while a somewhat superior light may be obtained from a small 

 lamp charged with kerosene, a larger lamp charged with lard oil 

 affords the greater illuminating power. So great is this difference 

 in lamps of the first order with five wicks, that the rates of light 

 from kerosene and lard, are as three to four respectively. Since 

 the safety of the keeper and the continuity of the light are essen- 

 tial elements in the choice of an illuminant, a thorough acquaint- 

 ance with the nature of the substance is essentially necessary. 

 "With a view therefore to the introduction of kerosene, a series of 

 experiments have been made during the last two years on the 

 different varieties of this material found in the market." J 



*"It has been established that the ordinary flre-test is insufficient as usually 

 applied, and that an explosive mixture may be fornied by confining the vapors 

 given off at a temperature in some cases twenty degrees lower than that certified 

 to by the public inspector. That this inquiry is of great pi'actical Importance to 

 the Liglit-house system, must be evident when we reflect that means niust be 

 devised for testing the oil oflfered for acceptance in accordance with contracts; 

 for storing it; for transporting it to light-house stations; for preserving It in 

 butts at tlie stations; and for the instruction of the keepers in its daily use." 

 (Report of L. H. Board, 1877, p. 5.) 



t Report of L. H. Board, 1875, p. 6. 



X Report of L. H. Board, 1877, p. 4. 



