THE YOUNG SCIENTIST. 
adapted substance that can be made avail- 
able for the purpose. Then, after the crys 
tals are cut in proper shape, they are put 
into a galvanic battery, which coats them 
over with a liquid, this latter being made of 
diamonds which are too small to be cut, and 
of the clippings and cuttings that are taken 
off of diamonds during the process of 
shaping them. In this way, all the small 
particles of diamonds that have heretofore 
been regarded as comparatively worthless, 
can now, by means of this ingenious French 
process, be made quite serviceable in the 
jeweller's art." 
Every statement in this paragraph is 
false. Any such working over of small 
particles of diamonds is, in the present 
state of our knowledge, an impossibility. 
Stones which pretend to be thus veneered 
are, however, largely sold, and the swindle is 
assisted by journals which publish, without 
comment, paragraphs like that just quoted. 
Liquefaction of Oxygen. 
OUR scientific exchanges come to us with 
the announcement that M. Pictet has 
succeeded in liquefying oxygen. If this be 
true, it is unquestionably the most impor- 
tant scientific feat of the year 1877. 
We must confess, however, that we have 
our doubts as to the truth of the statement, 
and for these reasons : In the first place all 
the accounts that we have seen are far from 
intelligible, but so far as they do convey 
clear ideas of the process, it would seem 
that oxygen, under a pressure of 4,800 
pounds to the square inch, has been sub- 
jected to a temperature of 140° below zero 
(centigrade). The pressure of the oxygen 
was obtained by generation ; that is, a given 
quantity of material capable of producing 
oxygen was placed in a retort capable of 
withstanding a pressure of 12,000 pounds 
per square inch, and when the gas was 
liberated, it produced the pressure stated 
(4,800 pounds per square inch) as there was 
no escape for it. The cold was produced 
by the evaporation of solid carbonic acid 
previously cooled by means of liquefied 
sulphurous acid. Now, all this has been done 
before, and to an enormously greater extent 
than is claimed by M. Pictet. Years ago 
Faraday produced a temperature of 110° C, 
by exposing a mixture of solid carbonic 
acid and ether to a vacuum. Natterer, by 
the use of bisulphide of carbon, instead of 
ether, in the above mixture, obtained a tem- 
perature of 140° C. 
As to pressure; a pressure of 4,800 pounds 
per square inch has been but a trifle these 
many years, and might at any time have 
been obtained with a single acting pump of 
good construction operated by hand. By 
means of a series of pumps, Natterer ob- 
tained a pressure of nearly three thousand 
atmospheres! (See Cooke's "Chemical 
Physics," pages 299 and 600.) To nearly 
this temperature and pressure did he subject 
oxygen, and yet he failed to liquefy it. 
The discrepancy here is so great that we 
feel there must be an error somewhere. 
Even if Natterer's estimates were too high, 
it is scarcely possible that he could have 
gone so far astray as to believe that he had 
nearly ten times the pressure that he had. 
On the other hand, it is unlikely that M. 
Pictet could have so greatly underestimated 
his temperatures and pressures; and it is 
still more unlikely that oxygen which has 
resisted 40,000 pounds per inch, and — 140°, 
should yield to 4,800 pounds per inch and 
— 140°. We are therefore afraid that M. 
Pictet has deceived himself, and that some 
impurity, or something similar, has been 
mistaken for the liquefied oxygen. We 
should, however, be glad to know that he 
has really accomplished this wonderful feat. 
Since writing the above, further accounts, 
giving more minute details, have reached 
us, and although the evidence in favor of 
the fact is not to our minds conclusive, we 
must admit that since such men as Berthe- 
lot, Sainte-Claire Deville, Boussingault, 
Mascart and others, men of great experi- 
ence in experimentation, have accepted the 
feat as accomplished, it is probable that the 
claims of MM. Cailletet & Pictet are well 
founded. But if so, the curious fact re- 
mains to be explained, that, with abundant 
means at their command, physicists have for 
years failed to accomplish the same thiug. 
