1882. 137 Trans. N. Y. Ac. Sez. 
rency of the crystals, and their perfection of form, render them quite 
remarkable. 
Mr. ARTHUR H. Extiott then read the following paper, which 
was largely illustrated with specimens of the various forms of ap- 
paratus described, and by experiments : 
THE METHODS OF ASCERTAINING THE SAFETY OF KEROSENE OIL. 
Before speaking of the various methods that have been proposed, and 
are now in use, for ascertaining the safety of kerosene oil, it will per- 
haps be well to look over the conditions of the problem. As we all 
know, kerosene oil is the product of the distillation of crude petroleum. 
This crude petroleum is made up of a number of oily liquids having 
different boiling points—in other words, liquids that give off vapors at 
different temperatures. These temperatures vary from 65° to 400° or 
500° F. From too parts of crude petroleum there is obtained by dis- 
tillation, in round numbers: 
penene ANADHENA, CLC. 2. io. » 2-5) ola es os oe © 15-16 parts. 
EGER, U7) Rk Se a te ean 55 parts. 
Paranme, Eubricatine Oils, etc.,2. 020-2... ..- 30; * 5 
It will thus be seen that only about half the crude petroleum is fit 
for burning. For the benzine, naphtha, etc., are too volatile and dan- 
gerous, while the paraffine is only fit for lubricating, being too thick to 
flow through an ordinary lamp-wick. On account of these two facts, 
the kerosene oil is the most valuable product of the distillation of crude 
petroleum, and brings the best price in the market. Benzine is worth 
only half as much as kerosene oil, while naphtha and paraffine bring only 
‘one-third as much. 
From these circumstances it follows that in distilling crude petro- 
leum, the oil-refiner tries to get as much kerosene oil in his product as 
possible. To increase the quantity of kerosene oil given by the petro- 
leum under treatment, the refiner may do one or both of two things. 
He may collect as kerosene those products which boil at either a lower 
or a higher temperature than good kerosene. The latter action is not 
so important as the former. In the last case an oil is obtained that is 
too thick and heavy to burn in ordinary lamps, and does not give a 
brilliant light. But in collecting the naphthas, which boil at a lower 
temperature than good kerosene, several very important results are pro- 
duced. Besides adding to the quantity of kerosene in the products, 
these low boiling oils increase very much the brilliancy of the light 
given by the kerosene. Here let me state exactly what I mean by this 
expression. I do not mean to say that the amount of light obtainable 
from a given quantity of low-boiling oil is greater than that obtained 
