212 ECONOMICAL LAMl*. 



It saved more ^g ^■^^r^y ^g^g observe, that the Ar^and lamp expends, la 

 tlian one third . o r i / 



of the oil. raising 20(X) grs. of water to the boiling point, 52-1 grs, of oil j 



and that the lamp just described requires only 33"3 grs. to pro- 

 duce the same effect, which is a saving of IS'8 grs. or more 

 than one third. 

 fh^eMamp^but ^^^- ^' -^^^^°"gh <^^^e ^a^p described in the last experiment 

 with the same did not produce an effect nearly equal to an Argand lamp, in a 

 *^a"° e'v"-4r" ^'^^" ^'™^ ' ^^^ ^ ^'^"^^^ clearly perceive that the principle upon 

 consumed 300 which it was constructed was good, and capable of being car- 

 grs. of oil per rigd to a much greater extent. I therefore ordered another to 

 hour, ana bo;!- , , . • .i i /- • t 



ed the water in "^ made, in every respect similar to the former ; except in the 



6J min. number of burners, which were increased to eight, each of 



which contained four threads ; so that the quantity of cotton 



Its effect was i" the wick of each lamp was exactly the same. This lamp 



therefore consumed 300 grs of oil in an hour, and made 2000 grs. of 

 equal to that ,.,.„? _ , \- , , ,• 



•f the Ar- water boil in 6-^ m. Its power, therefore, was equal to that of 



y;and lamp; an Argand lamp ; and if we take the quantity of oil consumed 



hut one thirJ , '^, ,/ . , . , ,,. . 



of die oil was ^>' ^" Argand lamp in heating to ebulhtion 2000 grs. of water 



saved. in 6| m. at 45 grs. (which is evidently too small a quantity) 



' and that consumed by this lamp, in producing the same effect, 



at 30 grs. the quantity required by the two lamps to produce 



a given effect, in a given time, will be in the ratio of 2 to 3. 



Exp. 4. smaller Exp. 4, a. The same lamp was used in this experiment, as 



ed more*oir™' *° ^^^ preceding ; but as four threads appeared to fill the tubes 



without in- too tight to admit the free ascent of the oil, only three wer« 



effect"^ ^^^^ put into each of them ; and a glass, 1-| in. in height, and 2 in. 



in diameter, was placed over the flame, as in an Argand lamp. 



When thus adjusted it consumed 320 grs. of oil in an hour; 



and caused 2000 grs. of water to boil in 6^ m. 



When the b. As the effect appeared to be somev/hat diminished by the 



>v!is"^!hm-t^ned elevation of the matrass to too great a distance from the flame 



the effect was of the lamp, this glass was removed, and another, only l in. 



increased : j^ height, substituted in its stead. The flame did not appear to 



be as vehement now as before : it nevertheless produced a 



greater effect, which was owing, no doubt, to the bottom of the 



matrass being nearly in contact with it. Only 276 grs. of oil 



were consumed in the hour 3 and 2000 grs. of water boiled 



strongly in 6^ m. 



anJ the saving This appears to be the preferable mode of using the lamp, a$ 



aearly one jj ^j^^g pioduces a greater degree of heat than an Argand lamp, 



even- 



