Scientific Lectures. 229 



the inflammability of these various products of petroleum. I should 

 be glad to illustrate the explosive character of mixtures of air and 

 the vapors of gasoline, naphtha and benzine, but some of my lady 

 hearers extracted a promise from me not to make any explosions, so 

 we will confine ourselves to the inflammability. 



This saucer contains gasoline. You see, the moment a flame 

 approaches, there is a flash from the ignition of the vapor, which 

 reaches out in every direction, and which conveys the flame to the 

 oil. "Water, you see, has no effect upon the flame, for the oil floats 

 on the water, and,- by spreading out the oil, the water actually 

 increases the flames. Now we will smother the flames by means of 

 sand, which covers and absorbs the gasoline, and excludes the air 

 necessary for its combustion. This second saucer contains naphtha, 

 which is not quite as volatile as gasoline ; still, you hardly notice 

 any difference in its inflammability when I apply the flame. The 

 same is true of the uenzine in this saucer, which is a little less volatile 

 than the naphtha. 



Here is a sample of the common, unsafe kerosene, which is so gene- 

 rally sold throughout the city. It has a gravity of 47° B., flashes at 

 51° F., and burns at 6S° F. You see, the moment the flame 

 approaches, it flashes and takes fire, almost as readily as the benzine. 

 This is a specimen of kerosene not as dangerous as the last, but still 

 many degrees below the standard of safety. It has a gravity of 47° 

 B., flashes at 82° F., and burns at 95° F. You see, I cannot cause it 

 to flash or take fire from a flame, yet when it has been burning an 

 hour in an orninarylamp, it will have reached a temperature at which 

 it will be dangerous. 



In these saucers are standard oils, " Downer's Standard Oil," " Astral 

 oil," and " Downer's Mineral Sperm." I cannot cause any of them 

 to flash or burn on applying a flame. 



Here is some of G. L. Smith's so-called " Safety Oil," which is sold 

 at 40 East Broadway. It is simply naphtha, having a density of 72° 

 B., and emitting inflammable vapors, and taking fire at all tempera- 

 tures. I have cooled it down as low as 18° F., and found it just as 

 dangerous as at ordinrry temperatues. You see how readily its vapor 

 takes fire now. 



This is Danforth's so-called " Non-explosive Petroleum Fluid." It 

 is simply naphtha, as is apparent from the readiness with which it 

 takes fire. 



It is a pity Smith and Danforth do not furnish fire extinguishers 

 together with the naphtha. They both claim that they have rendered 



