ECONOMICAL LAMP. 



213 



even under the most favourable circumstances ; and consume3, 



in the same time, 224 grs. less of oil, which is a saving of about 



-2%, or nearly half. If we calculate the quantity required by 



each to produce the same effect, it will be still more in favour 



of mine. 



Exp. 5. a. As the advantages arisino: from bringing the sub- ^•^P ^.Theef- 

 ^ => ^ f<^ct of Ar- 



stance to be heated, as near as possible to the flame ot the lamp, gand's lamp is 



appeared to be so considerable, it was natural to conclude, that '^^^ when the 

 similar effects would attend the shortening of the glass of the f^^ay? 

 Argand lamp, or the removing it altogether. Accordingly, 

 2000 grs. of water were exposed to the heat of this lamp, 

 when burning as clear as possible, without a glass. The water 

 did not boil in less than 7f min. This, therefore, did not ap- 

 pear to be any improvement. 



b. I added to the Argand lamp a glass 2 in. in diameter, and But a short 

 ]| in. in height, from the base of the flame. Its power was fjng^^'saif/one 

 considerably increased, for It made 2000 grs. of water boil in hiih of the oil 

 Qx m. and consumed only 400 grs. of oil per hour. *" the A. lamp. 



Those who do not think it worth their while to piocure a 

 lamp similar to that which I have recommended, will at least 

 find it a considerable improvement, to reduce the glasses of 

 their Argand lamps, to the dimensions here specified, which will 

 cause a saving of one tifth of the quantity of oil at present 

 consumed. 



Exp. 6. One of my principal objects, in the construction of Exp. 6. The 

 this lamp, was, that I might be able always to procure an equal ^^^^ j^^^ ^^ 

 degree of heat ; and one that could be augmented or diminished steady, and is 

 uniformly. The following experiments were instituted with a fJX^^numbtr 

 view to determine, whether it possessed these properties or not. of burners, 

 I have arranged them into a table j 



7 

 6 

 5 

 4 

 3 

 2 

 1 



the first column of which indicates the number of burners em- 

 ployed ; the second^ the time required to raise 1000 grs. of 



m. 



m. 



34 





4 



4 



4|- hardly 



4f 



0' nearly 



5-6 



6f 



7 



.9^ 



9i 



15 



14 



30 



23 



