APRIL 29, 1915] 
NATURE 
233 

a 12-in. column and then through dephlegmators, 
which cut out the heavier portions of the residue, 
the vapours and gases passing on into a con- 
densing chamber, where they are compressed to 
100. lb., and under this pressure go through the 
condensing coils. There seems to be an endo- 
thermic reaction taking place during the con- 
densation by pressure, as a fall of temperature 
takes place where one would have expected a rise 
from the compression, and the liquid finally con- 
densed contains not only gas in solution, but 
excessively volatile hydrocarbons evidently formed 
by the nascent gases attaching themselves to 
other molecules or polymerising. Such a spirit 
is far more complex than one formed by dissocia- 
tion acting alone, as, besides the paraffins, ole- 
fines, and naphthenes, we also find aromatic 
hydrocarbons, acetylenes, and bodies like hemi- 
terpene and terpenes. 
During the past ten years several processes 
have been introduced in which steam or water 
has been introduced with the oil into the cracking 
ducts, the idea being that hydrogen from the 
water would affix itself to the heavy hydrocarbons 
and hydrogenate them into lighter hydrocarbons ; 
to aid this action catalysts have been frequently 
used, nickel being the most popular. 
The idea of the use of nickel as a catalyst is 
twenty-seven years old, as, in 1888, Ludwig 
Mond took an English patent, 12,608 of that year, 
in which he mentions the treatment of hydro- 
carbons, together with steam, by passing them 
through heated vessels containing fire-brick or iron 
oxide, and he states that if metallic nickel is used 
in place of the iron oxide, then only a moderate 
temperature is required. 
About 1900, Sabatier and Senderens studied the 
action of nickel and other metallic catalysts on 
the hydrogenation of oils, and in the following 
years there were many more patents taken cover- 
ing its use. Still later there were a large number 
of patents taken in America by Dr. Day, Ellis, 
’ Kayser, and others, dealing with the use of nickel 
as a catalyst. 
Mond, Sabatier, and Senderens all recognised 
that such surface action as the nickel exercised 
took place only at temperatures below, at any 
rate, 300°C., but the more recent exploiters of 
the idea have drifted back to the temperatures one 
would use for cracking, not for hydrogenation. 
Mr. Edgar A. Ashcroft has been doing some 
extremely interesting and highly suggestive work. 
Starting with the theory that the crude oil, as we 
obtain it from the well, represents a mixture in 
which the groups of atoms forming the molecule 
have, under the influence of temperature and 
pressure existing during the formation of the oil, 
arranged themselves as compounds in a propor- 
tion that has given a natural equilibrium, he 
suggests that if the crude oil be distilled so as 
to eliminate the lighter fractions and the residue 
be again subjected to the same temperature and 
pressure as that at which it was formed, a natural 
equilibrium will again be reached by the forma- 
tion of a mixture akin to the original crude oil, 
NO. 2374, VOL. 95] 
| from which more light fractions can be distilled. 
In the same way, when coal is destructively dis- 
tilled, the gas and tar represent a molecular 
arrangement which is in a state of natural equi- 
librium, so that by taking a middle fraction of 
the distillation of such tar, say creosote oil, and 
subjecting it to heat and pressure, tar, with its 
low boiling hydrocarbons, middle fractions, and 
pitch, should be again formed. That this is so is 
seen from the following experiment. 
Two hundred c.c. of creosote oil, distilling 
between 240°C. and 350°C., were heated in an 
autoclave up to 490°C., which gave a pressure 
of 100 atmospheres; on allowing to cool down 
180 c.c. of tar and 5 litres of very rich gas were 
found to have been formed. The tar on distilla- 
tion gave :— 
c. Cc. 
First runnings, up to 170° C. 10 ©Benzol, toluol, and 
solvent naphtha 
Carbolic oils, 170°-240° C. 2720 \ Phenols, naphtha- 
Creosote oils, 240°-270° (Ge 520 lene, and anthra- 
Anthracene ae 270° oe (Gs fooo HO j cene 
Pitch (very fine) . 5 . 30 
representing an ideal benzenoid tar. 
The extreme suggestiveness of this work, both 
from the theoretical and commercial point of view, 
will be at once apparent as offering a method by 
which the least valuable fractions of tar and crude 
oil can be converted into those for which there is 
a greater demand. 
SERVI SERVORUM DEI. 
[2 is not only His Holiness the Pope who is 
servant of God’s servants; the title well 
becomes all who are saving or safeguarding the 
health of the British Expeditionary Force. To 
read the medical and surgical history of past wars 
—the American Civil War, or the Crimea, or the 
Franco-German War—is more pain than pleasure. 
To read what our Army Medical Service is doing 
now—a Committee has just been appointed for the 
writing of this history—will be not the least of 
the pleasures of peace. We have a foretaste of 
it, in the article which was published in the daily 
papers last week, by “an Eye-Witness present 
with general headquarters." He says, to begin 
with, that a war such as this, with so much hard- 
ship and exposure, would have cost our nation, a 
few years ago, an outbreak of disease that w ould 
have decimated our forces. He goes on to say that 
the low sick-rate in the Army to- ~day i is due, partly,’ 
to the diligent instruction given of late years to 
our men in the first principles of health. “In the 
main, however, it is due to the prev entive 
measures adopted by the medical service.” And 
these preventive measures are of two kinds: those 
which prevent infection from gaining access to 
our men, and those which strengthen our men to 
withstand infection. 
The article is mostly concerned, and no wonder, 
with typhoid fever. Yet, if we think of single 
cases, not of masses of cases, the protective treat- 
ment against tetanus, surely, is not a less achieve- 
| ment ‘than the protective treatment against 

