198 
NATURE 
[APRIL 23, 1914 
Ix a recent number of the Annalen der Physik there 
appears an important paper by Prof. Quincke on 
“Electrische Schaumwiinde der Materie.’’ The sub- 
ject-matter is a continuation of the work which has 
been done on the structure of ‘foam’ walls and 
chambers, but in particular he poiats out an analogy 
between these and the electrical ‘‘dust”’ figures, 
which he regards as being due to the formation of 
foam chambers by electrical emanations of positively 
or negatively charged particles. Ordinary foam 
chambers made by precipitation or other methods he 
regards as being of two kinds: (1) those formed 
quickly in viscous fluids, and which may take a 
variety of forms, (2) those formed slowly in less 
viscous fluids, and which consist of globular cells 
connected by tubes. When the charged knob of a 
Leyden jar is presented to a cake of resin, he supposes 
that an electrical emanation of charged particles is 
emitted, and these particles are attracted to the plate 
of resin. By their impact they melt the resin locally 
to form an oil-like substance which solidifies around 
the charged particle, and thus produces a ‘“foam ”’ 
chamber with electrified walls. These chambers are 
rendered visible by dusting with the usual mixture of 
red lead and sulphur. He regards those upon which 
the sulphur is deposited as being similar to type (1), 
and those upon which the red lead settles as being 
similar to type (2). 
Nearty all the optically-active carbon compounds 
that have been prepared hitherto have been substances 
of relatively complex composition. The two simplest, 
lactic acid, CH,.€H(OH).CO,H, and sec.-butyl 
alcohol, CH,.GH(OH).C.H,, contain three and four 
carbon atoms respectively; in each case also three of 
the four radicles attached to the asymmetric carbon 
atom G are compound radicles, and only one ~(the 
hydrogen atom) is simple. Special interest attaches 
therefore to the two simple substances, ammonium 
d- and I-chloroiodomethanesulphonates, 
CHCII.SO,.ONH,, 
which have been prepared and separated in an optic- 
ally-active form by Prof. Pope and Mr. Read (Trans. 
Chem. Soc., 1914, vol. cv., p. 811). In these sub- 
stances three of the radicles are simple, and only one 
is compound; none of the four radicles contains a 
carbon atom, and the percentage of carbon amounts 
to less than 5 per cent. The two acids were separated 
by fractional precipitation from the ammonium salts 
by the addition of brucine; after reconverting into the 
ammonium salt the dextro-acid gave the molecular 
rotation [M]j.0. +43°- The active material is remark- 
ably stable; the optical activity is not changed by 
boiling alone or with acids or alkalis, or by heating 
with water in a sealed tube to 130-150°. 
Engineering and the Engineer for April 17 contain 
articles dealing with electric power supply in London. 
Messrs. Merz and McLellan have investigated this 
subject recently, and have presented a report to the 
London County Council. Apart from traction stations 
there are seventy generating stations at present in 
London, containing 585 engines. The report states 
important economies in electricity generation in Lon- 
don; first, to allow the extension of eight or ten of the 
best existing stations, and gradually to abandon all 
the others; secondly, to abandon all sites in or near the 
metropolitan area, and to concentrate the production 
of electricity for all purposes well. outside. The 
primary distribution system throughout London should 
be standardised. Assuming all existing stations for 
the supply of light and power to be in the hands of 
one authority, the final conclusions are that it would 
pay to shut them all down, sell most of the plant, 
and generate all energy on sites down the river. Con- 
sidering only the central area, it is estimated that the 
saving in working costs with this scheme would be. 
about 18 per cent., or 170,000l. a year. 
Tue editor of the new quarterly, Isis, devoted to 
the history and organisation of science, asks us to say 
that the annual subscription is 30 francs per annum, 
and not 24 francs as stated in a note in Nature of 
April 9 (p. 143). 
A copy has been received of the second supplement, 
| 1911-13, to the catalogue of Lewis’s Medical and 
| Scientific Circulating Library, 136 Gower Street, Lon- 
don, W.C. A classified index of subjects, with the 
names of those authors who have written upon them, 
is included. 
OUR ASTRONOMICAL COLUMN. 
Comet 1914a (KRITZINGER). — The following 
ephemeris of comet 1914a (Kritzinger) is published by 
Prof. Kobold in Astronomische Nachrichten, 
No. 4727 :— 
12h. Berlin M.T. 
R.A. (true Dec. (true) Mag. 
m. s. = ; 
Aprmbes «:.. 7 2S 0RG +8 45:2 0:5 
24; 42 30 9 40°7 
25 46 27 10 36-6 
26 50 2 II 32-7 9:4 
27 54 23 I2 29-0 
28 17 58 23 13 25:4 
2 OP a3 Om 2ead 14 21:9 
FO" ee 18° 6127 +15 18:3 93 
THE VARIABLE 081041, — 41° 3911, H.V. 3372.—Prof. 
E. C. Pickering communicates some interesting facts 
relative to the spectrum and magnitude of the star 
C. DM. —41° 3911, this star having previously been 
found by Mrs. Fleining to be peculiar, and also later 
independently by Miss Cannon. In identifying this 
object Miss Mackie has found that it is a variable, and 
in this paper the magnitudes are given for the period 
1890 to 1912. The nature of the variation is indicated 
by a curve. Prof. Pickering describes the object as a 
very curious one. At first sight it might appear to 
be a variable star with a period of about twenty years, 
and varying from the eleventh to the fourteenth mag- 
nitude. He points out that ordinary variables of long 
period have a very different spectrum and undergo all 
their changes in less than two years. In this case 
the variations may prove to be irregular and to re- 
semble those of the three stars of the class. of 
R. Corone. The position of the star for rg00 is R.A. 
8h. 10-8m., and declination —41° 24’, and additional 
observations of both its magnitude and spectrum are 
required to settle the peculiarity above mentioned. 
THE SOLAR CONSTANT OF RapraTion.—No one in- 
terested in this subject should fail to read an address 
that there are practically only two ways of effecting | delivered before the Philosophical Society of Washing- 
NO: 2321, VOU. 03) 
