
A Neglected Correction in Osmotics. 
In the dynamic method of determining relative 
vapour pressures, air, initially dry, is passed first over 
the solution and then over the pure solvent. When 
it leaves the solution it has taken up a quantity of 
solvent vapour 1,; on leaving the solvent it contains a 
further quantity, 1,—1,. While working on aqueous 
solutions at o° C., Mr. Hartley and I had realised that 
the air when over the solution expands by an amount 
represented by the vapour pressure of the solution, 
similarly a further expansion takes places over the sol- 
vent, but as this further expansion is only that due to the 
difference of vapour pressures of the two liquids—say 
1/1oth of 4 mm, Hg—we had assumed that this small 
quantity was negligible in comparison with the total 
pressure. 
Dr. C. V. Burton, of my laboratory, has pointed 
out to me that this assumption is not justified when 
osmotic pressures are to be calculated from the ob- 
served results. His discussion of the necessary cor- 
rection is as follows. Let B be the barometric pres- 
sure and V the volume of air (measured when dry) 
passed through the system. The air in contact with 
the solution has a partial pressure of B—z-, and the 
volume now occupied by it is increased to VB/(B—z,). 
Similarly, on leaving the solvent the volume has 
become VB/(B—z,). If p, and p, are the densities 
of the vapour in equilibrium with the solution and 
solvent respectively, the masses 1, and /, are 
p,VB/(B—z, and p,VB/(B—z,). 
Assuming that Boyle’s law holds good for the vapour 
- up to z,, with sufficient accuracy for the purpose of 
the correction, we can replace mz by z,p,/p,- We have 
then what amounts to a simple equation in p,/p,; its 
solution is po/p, =4,/Z, — = (4 - 1). 
BANG 
In the value deduced for the osmotic pressure, 
log.(p,/p,), enters as a factor, and the corrected value 
of this factor is log,(/,//,) - log.| 70(— I ) | 
SEN 
The correction for a solution at 0° C., the osmotic 
pressure of which is 132 atmos., is —o-84 atmos., and 
for one the osmotic pressure of which is 41 atmos, it 
is —o:26 atmos. BERKELEY. 
Foxcombe near Oxford. 
Chemistry and Industry. 
In his admirable article in Nature of February 18 
under the above heading, Prof. Jocelyn Thorpe dealt 
in a very concise manner with the grave difficulty 
which must seriously hamper all the present efforts 
to establish chemical industries in this country in 
successful competition with Germany. Particularly 
his remarks that the scientific worker has found by 
sad experience that little financial profit accrues to 
him even though he goes to the trouble of obtaining 
patent protection for his discovery, are of interest. 
In this country, when an inventor applies for patent 
protection, a novelty search is made by the Patent 
Office in respect of his invention, solely among 
British patent specifications published before the date 
of his application during a period of fifty years. In 
contradistinction thereto the examiners at the German 
Patent Office investigate all printed publications of 
the last one hundred years prior to the date of such 
application. These publications include not only Ger- 
man patent specifications, but patent specifications and 
text-books of every country in the world. The appli- 
cant’s attention is directed to any prior publication 
or text-book dealing not only with the particular sub- 
ject but containing even remote suggestions that may 
lead up to that particular discovery. 
NO. 2367, VOL. 95] 
NALS RE, 
[Marcu 11, 1915 

Now, while this somewhat gigantic problem of the 
German Patent Office cannot in all cases be efficient 
and free from fallacy, it is, nevertheless, quite clear 
that the result of such a search must in a large 
number of cases be of greater value than that of the 
limited search carried out by the British Patent Office. 
In this manner, therefore, the inventor, if his discovery 
is found novel and patentable in Germany, has not 
only the satisfaction of having his invention tested 
quasi from an international point of view, but what 
is more valuable to him, he has his attention directed 
to knowledge existing and discoveries made also out- 
side his own country. ‘ 
Due to this wide scope of the official search, apart 
from other stringent considerations connected there- 
with, fewer patents are, of course, granted propor- 
tionately in Germany than are granted in this country, 
and it would, indeed, be interesting to examine how 
many of the discoveries for which patents have been 
granted in this country, for instance, in respect of 
aniline dyes, have, in fact, been protected also in 
Germany. A number of these British patents on 
which royalties are probably being paid, or will be 
paid in the near future, would, perhaps, not stand a 
test before our courts, since prior text-books or a prior 
foreign specification may be relied upon in an action 
before a British Court, while the Comptroller-General 
of Patents has no right to consider such publications 
before granting a patent. 
I have heard it argued that our limited search was 
good enough, because if there was anything worth 
patenting anywhere, it would certainly be patented in 
this country. I venture to suggest that this is as 
much an antiquated idea as prevailed, until this war 
opened our eyes to the present industrial situation, 
with regard to the industrial supremacy of these 
islands shortly after the time when Section 27 of the 
Patents and Designs Act of 1907 was called into being. 
In this connection it is interesting to recall a famous 
phrase uttered by Mr. Justice Parker (now Lord 
Parker) in his decision in the matter of the revocation 
of Hatschek’s patents, Nos. 6455 of 1900 and 22,139 
of 1900, viz. :—‘‘ However great may be one’s belief 
in the industrial supremacy of the inhabitants of these 
islands, it would at least be somewhat arrogant to 
assert that wherever the manufacture of a patented 
article in the United Kingdom is less than one-half of 
the total manufacture of the whole world, there arises 
a presumption that British trade has not had fair 
play.” 
The decision involved a matter of great importance 
to patentees, manufacturers, and British traders, and 
it was justly stated that the whole industrial world 
was anxiously awaiting the dictum on that famous 
section of the Act. 
The greatest anxiety, of course, prevailed in Ger- 
many, and this was natural in view of the many 
British patents taken out by German chemists and 
chemical concerns for the purpose of biocking the 
industry in this country rather than of developing it. 
Now, why has that section failed to do that which 
it was actually framed for? To my mind there are 
several important reasons. The average manufacturer 
does not possess the knowledge that chemical manu- 
facture cannot in these times be carried on without 
his close co-operation with highly trained chemists, 
and, true to old-established tradition, he is prejudiced 
to any such co-operation. Further, he is constantly 
faced by the danger of infringing existing British 
patents, and even though he may be aware that the 
patents blocking his way are mere ‘paper ”’ patents 
and that he has every reasonable hope to succeed in 
an action for infringement or revocation thereof, the 
exceedingly high cost at present connected with any 
' action must have an important effect on his hesitative 


