FIEE AS AN AGENT IN HUMAN CtTLTUBE 223 



Since the time was not yet for the production of the ideal fuel, the 

 earlier inventions dealt with the problem of the increased oil suppl}'' 

 to the wick by hydrostatic principles. Natural gravity pressure, it has 

 been seen, was employed in north European folk lamps of the seven- 

 teenth and eighteenth centuries, perhaps earlier. With the increased 

 oil supply the wick must be designed to burn the fuel furnished, and 

 this introduces proper aeration to prevent smoke. The ancient 

 round wick of yarn produces an excess of unconsumed products in 

 the midst of the flame; woven flat wicks are better. About 1780 

 tubular wicks furnished complete aeration and the burner was given 

 draught by openings under the flame, a principle long before incor- 

 porated in the stove. The draught was brought up through the 

 burner, aerating both sides of the flame and doing away with the 

 center of incombustion. The chimney of Argand added the last 

 essential. 



A considerable school of inventors interested in the perfection of 

 the lamp was at work about the period of Argand, and, as is usual 

 in such cases of rapidly focussing inventive thought, it is difficult 

 to definitely place credit for various features. The Swiss engineer 

 Argand, however, is to be given credit for the advanced lamp, his 

 efforts being to perfect the burner and to increase still more the 

 draught by the chimney. Much later artificial or forced draught was 

 applied. The fuel question had not been solved, but the advance of 

 chemistry was bringing out products of possible value. The vegetal 

 and animal oils in use in the early stages of the invention were of heavy 

 body, and various devices utilizing mechanical pressure characterize 

 the lamps at the close of the eighteenth century. 



The lamps of the folk pursued a line of development of their own 

 without regard to the advanced lamps, which were costly and often 

 erratic in behavior. At some period not to be stated the immemo- 

 rial lamp with wick to edge in a spout was abandoned and the wick 

 was installed in the center of the reservoir. Argand's lamp and 

 many others were based on the ancient model. The central-wick 

 lamp is the ancestor of modern lamps. 



The lamps which came in number and variety, many of them very 

 ingenious from the workshops of French and English inventors were 

 articles of luxury, little affecting the slowly developing fighting appli- 

 ances of the people."^ George Washington possessed several lamps 

 of the Argand type, perhaps duplicated in few of the great houses of 

 America at the close of the eighteenth century. The popular lamp 

 and the general diffusion of illumination awaited the discovery of a 

 suitable illuminant. 



"It is not intended here to review in detail the history of the lamps of the inventive period. 



