682 TRANSACTIONS OF THE 



admitting oxygen to the centre of the flame. The flames of dif- 

 ferent substances do not all form an equal production of light and 

 heat. Phosphorus burns with a dense flame ; sulphur a weak 

 one ; spirit of wine a slight but very powerful one in respect to 

 heat. 



The vegetable oils used for light, are olive oil, which burns 

 with a beautiful white light, fully equal to wax, free from any 

 offensive smell while burning, but is rather expensive. Tobacco 

 and belladonna oils, mild and much used in Germany j Colza oil, 

 extracted from the seeds of a species of cabbage ; oil of plum 

 stones ; cocoanut oil j palm oil, from which steam is obtained ; 

 whale oil, &c. Then we have vegetable wax candles ; myrtle- 

 berry wax ; mineral wax ; Breckenridge coal wax ; spermaceti ; 

 tallow; dipped; mould; and stearin. There are many lamps in 

 general use, but among them all I prefer the Carcel, which gives 

 a beautiful light — the oil is raised through tubes by clock work, 

 in such a manner as to keep the wick thoroughly soaked; it will 

 burn eight hours with unabated splendor. 



If a lighted candle is projected between you and the sun, the 

 wick only is perceived, which presents the appearance of a black 

 spot. The intensity of the flame of a wax candle, is equal to the 

 fifteen thousandth part of a corresponding portion of the sun's 

 rays. The brightest light ever produced by man, was engendered 

 by the aid of a galvanic battery, and it compares favorably with 

 solar light, being equivalent to three thousand eight hundred wax 

 candles. The direct rays of the sun are equal to five thousand 

 six hundred wax candles, placed fourteen inches from the object, 

 and the moon to the light of one candle at the distance of thir- 

 teen feet. The light of the sun is one million times greater than 

 the light of the moon, and millions of times greater than all the 

 fixed stars taken together. 



The Chairman called up the regular subjects : "Pavement and 

 photography." 



Mr. Pratt desired to explain further his steam plow, which he 

 did by drawings on the black-board and by description. 



Wm. B. Leonard, for Thaddeus Selleck, exhibited his new plan 

 for pavements. It consists of cast iron frames, two feet long and 



