1887.] MICROSCOPICAL JOURNAL. 17 
CORRESPONDENCE. 
Benzine, Benzole, and Alcohol. 
To THE EpITor :—I notice in the November number an inquiry as to the above 
substances. 
The first, benzine, is a trade name for one of the liquids into which crude petroleum is 
separated by the process of fractional distillation, usually that which comes off between 
the temperatures of 200° and 300° F.(approximately) just before kerosene. It isa mixture 
of several compounds of carbon and hydrogen,C,H,, and C, ,H,, being usually present. 
It has a well-known rank odor, is a good solvent of fats, but is not miscible with alcohol, 
and hence not adapted for microscopic work. Itis very cheap and much used for clean- 
ing clothes without water; hence the French say ‘dry cleaning.’ Benzole is a chemical 
compound, C, H,, named by Mitscherlich, because made by distilling benzoic acid and 
lime. It is zo¢ obtained from petroleum, but is now chiefly got from the distillation of 
coal tar or oil shale. Its odor is much more agreeable than that of benzine, being slightly 
aromatic; it mixes in all proportions with alcohol, and I have thought it did not extract 
the color from stained preparations, when used as a solvent for balsam, so much as 
alcohol ; and, on the whole, I prefer it for mounting. As it is not produced in the state 
of purity required by the microscopist, on a large scale, it is necessarily expensive, most 
of what I have used being prepared by Merck. Besides the differences noted, benzole, 
with nitric acid, makes nitro-benzole, but benzine does not; a crystal of iodine dropped 
into benzole gives a violet color, but with benzine red. Benzole has specific gravity, 
0.86; benzine about 0.73 to 0.76. Absolute alcohol may be prepared most easily by. 
Squibbs’ method. Have a row of several jars; for small quantities fruit-cans will do. 
Provide fresh-burned lime and partly fill the jars. Fill the first jar with common alcohol, 
and after a day or two pour it into the second jar, refilling the first with more common 
alcohol. Blue vitriol or cupric sulphate contains water of crystallization, all of which 
is driven off at 430° F., when it turns white. This may be done onashovel. After pass- 
ing the alcohol through several jars, as above, drop in it a white crystal of the copper 
salt; if it stays white, all the water is removed. The time and number of jars required 
will depend on the strength of the alcohol first used. After the alcohol is made anhy- 
drous, or nearly so, it will absorb moisture from the air; if kept in a bottle partly full 
or left open, it is difficult to maintain it more than 96%. Frequently the cloudiness that 
forms in a preparation by precipitation of gum, when the alcohol is not quite absolute, 
will vanish in a short time if left to itself. 
1424 Eleventh st. N.W., Washington, D.C. Wy. H. SEAMAN. 
[A method of making absolute alcohol, referred to in brief in the November number 
of this Journal, is described in the Am, Micr. Journal, vol. vi, p. 119, 1885, from Jour. 
Roy. Micr. Society.—ED. | 
O 
To THE EpIror :—Some time ago a German calling himself H. Hensoldt called on 
us, and offered us objectives with the name,.etc., of Carl Zeiss, in Jena, pretending that 
they were the new apochromatic objectives, and that he was one of Mr. Zeiss’ former 
workmen and knew all about these lenses. The low prices he offered them at, and the 
difference in workmanship (his being made in an inferior manner), induced us to inquire 
of Mr. Zeiss. The answer was that such a man was not known to him, nor did he ever 
get any objectives out of his place. Mr. Zeiss further requests us to do our best in coun- 
teracting the swindle of this person, and even to have him arrested if found out. We 
request you to give this information publicity in your /ourvma/so as to warn your readers 
and the public from purchasing or believing in the assertions of this swindler. 
igo FULTON S1.;)N./Y: Fr. J. EMMERICH & SON. 
——0o 
To THE Epriror :—I have a slide of diatoms from Ichabce guano of 1844, mounted 
by Topping. In looking it over, a few days ago, I noticed quite a large number of 
dermal spicula of the fresh-water sponge, Sfongzl/a lacustris. There are also many 
skeleton spicula of several forms, but these may be marine, while the dermal spiculum, 
with its characteristic curves and spines, are unmistakably of the fresh-water species. 
There are also some half-dozen large and well-formed birotulate spicula, which are 
only known in fresh-water sponges. All this proving that the birds must have lived 
on food from fresh water. Having supposed that guano was the product of sea dzrds, 
which, as a matter of course, obtain their food from the ocean, I was surprised to find 
