224 BULLETIN 139^ UNITED STATES NATIONAL MUSEUM 



Illuminating fluids were the object of earnest research carried on 

 by investigators in various European countries and in America. The 

 more important of these put in general use were whale oil, preferably 

 of the sperm whale, Physeter macroceyhalus ; lard oil; paraffin oil 

 made by distilling oil shales, and cannel coal, 1834-1850; camphine, a 

 compound or distillate of turpentine oil over chloride of lime, a dan- 

 gerous explosive, about 1830, and finally the ideal was reached by 

 the discovery of petroleum in great quantities at Titusville, Pennsyl- 

 vania in 1859, and the distillation of its chief constituent, known as 

 coal oil, thus solving the problem of nearly a century. The earher 

 lamps burning heavy oils had one central wick tube without device 

 for raising or lowering the wick. Following Franklin's scientific 

 discovery based on observation of the common lamp, proving that 

 two tubes side by side produced proportionately more light by 

 induced draught, changes to this effect were made in lamps. Three 

 tubes, it was found, produced a contrary effect. On the introduction 

 of camphine tubes were made longer and inchned at a diverging 

 angle. At this period also special burners were devised for burning 

 camphine. 



In the sixties in the United States the use of petroleum became 

 general and the common two-tube lamps were mounted with venti- 

 lated burners and glass chimneys. These lamps had flat wicks. At 

 the Centennial Exhibition in Philadelpliia in 1876 there was exhib- 

 ited a lamp with tubular woven wick, center ventilated, and with 

 glass tubular chimney having an expanded air chamber at the base. 

 This lamp was the beginning of a line of lamps reaching the highest 

 illuminating results from petroleum (pi. 41, fig. 5). 



ETHNOGRAPHY OF THE LAMP 



Under this head are discussed lamps which different races have 

 adapted to their needs and which show racial characteristics in art. 

 These lamps belong in the noninventive period, and therefore pre- 

 cede developmentally the lamp of Argand. It is obviously impossible 

 to monograph the lamps of each country treated below. An attempt 

 will be made only to present the characteristic forms coming to 

 notice. 



ENGLAND 



Extemporaneous or local lamps are interesting as devices of the 

 folk, although they have no bearing on the history of illumination. 

 England has many of these which their makers fashioned as an 

 expression of humor or individuality. Thus a block of chalk hollowed 

 out and squared forms a lamp such as it is, or an excavated turnip 

 is made into a temporary oil holder. 



