May 16, 1912] 
and leakances (S, in mhos) have been converted into 
resistances in ohms 
I I 
iN ip ay 
The general network problem then is to find the cur- 
rent, in amperes, in any given branch, corresponding 
to the application of an E.M.F. of sine form, between 
any two fixed points in the network. 
\ 
Lip, where /=47~ h 
MANCHESTER. 
Literary and Philosophical Society, April 23.—Prof. 
F. E. Weiss, president, in the chair.—R. L. Taylor: 
The action of bleaching agents on the colouring 
matter of linen. The author showed that the colouring 
matter of unbleached linen is quite abnormal with 
regard to the action of the ordinary bleaching agents 
upon it, and differs from every other colouring matter 
with which he is acquainted. | Whereas colouring 
matters, such as indigo, Turkey-red, and the colour- 
ing matter of cotton, are bleached much more rapidly 
by free chlorine or hypochlorous acid than by a hypo- 
chlorite, with the colouring matter of linen the exact 
opposite is the case, this being bleached more rapidly 
by a solution of a hypochlorite. Apparently the maxi- 
nium bleaching effect on unbleached linen is pro- 
‘duced by a solution of a hypochlorite which contains 
no free alkali, but rather some free chlorine or hypo- 
chlorous acid. Excess of alkali retards the bleaching 
action, just as it does in the case of other colouring 
matters. The addition of a chloride to the solution 
sometimes accelerates and sometimes retards the 
bleaching action (this depending upon the amount of 
alkali in the solution), instead of, as is the case with 
other colouring matters, always accelerating it. 
; Care Town. 
Royal Society of South Africa, March 20.—Mr. S. S. 
Hough, F.R.S., president, in the chair.—L. Perin- 
Suey : Bushman sticks decorated on intaglio and poker- 
work, a note on the decorative skill of the Bush people 
and other aborigines. Specimens of sticks, decorated 
with drawings and carvings, also bust models, &c., 
were exhibited. On the sticks the intaglios were 
extremely fine, and represented hunting scenes, in 
which men in police uniform and on horseback were | 
depicted with most consummate skill; other sticks 
were ornamented with poker-work and line drawings 
of very great artistic merit, but representing modern 
subjects, a railway train among them. Poker-work 
was, in his opinion, probably of Kafir origin, and it 
Was quite possible that the Bush people had obtained 
it from the latter, but improved on it through their 
natural artistic disposition. _ He had at one time 
doubted the authorship of rock-graving in connection 
with the Bush people, but he exhibited a Bush paint- 
ing in which the back of the animals had been 
graved. The Bushman thus combined the two arts, 
graving and painting.—J. R. Sutton: Some meteoro- 
logical conditions controlling nocturnal radiation. 
According to the results obtained, it appears that after 
allowance has been made for the state of the sky and 
the movement of the air, the only factor of real 
importance determining the radiation temperature 
gradient is the relative humidity.—T. Muir: The 
resultant of a set of homogeneous lineo-linear equa- 
tions. Three different methods are given for obtain- 
ing the resultant, but the main interest is concen- 
trated on one of them, because of two or three some- 
what obscure references made to it by Sylvester when 
studying the problem in 1863.—W. A. Douglas Rudge : 
The variation in the value of the atmospheric elec- 
trical potential with the altitude. This paper gives 
some account of observations taken at various places 
in South Africa in order to find the relation which 
NO. 2220, VOL. 89] 
NATURE 
287 
exists between the atmospheric potential gradient and 
the altitude of the places of observation. Observa- 
tions were taken between Lourenco Marques and 
Durban, via Johannesburg, passing thus from sea- 
level to sea-level over a considerabie stretch of country 
in which the altitudes rose to nearly 7ooo ft. The 
general result is that there is a great change in the 
value of the potential gradient with the altitude, the 
extreme value at the highest point (6500 ft.) being 
not more than one-eighth of that at sea-level. Similar 
differences having been observed on previous occa- 
sions at other places, led to the investigations being 
conducted. ©The maximum values were about 500 
volts per metre at Lourenco Marques and Durban, 
and 58 volts at Belfast, 6500 ft. above sea-level, and 
at places in between values were obtained which 
showed that the greater the altitude the smaller the 
potential gradient. An exception to this rule was 
seen at Johannesburg, where the potential gradient 
was very variable and changed signs at different 
points in the neighbourhood. These variations were 
traced to the clouds of steam, and especially of dust, 
proceeding from the mine heaps. Steam has the 
effect of increasing the positive gradient, while dust 
lowers it—H. A. Wager: Respiration and cell energy. 
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Mechanics of the Aéroplane. By Captain 
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Richtlinien des Entwicklungs- und Vererbungs- 
problems. By Prof. A. Greil. Erster Teil. Pp. iii+ 
352. (Jena: G. Fischer.) 10 marks. 
Building Stones and Clays: their Origin, Char- 
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264. (New York: J. Wiley and Sons; London : Chap- 
man and Hall, Ltd.) 12s. 6d. net. 
German Varnish-making. By Prof. M. Bottler. 
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Varnish and Paint Manufacture, by A. H. Sabin. 
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don: Chapman and Hall, Ltd.) 15s. net. 
Canada. Department of Mines. Mines Branch: 
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McGill University, Montreal, under the Authority of 
The 
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Porter and R. J. Durley and others. Vol. i. Pp. 
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The Elements of Statistical Method. By W. I. 
King. Pp. xvit+250. (London: Macmillan and Co., 
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Zoology. By Prof. J. G. Kerr. Pp. vii+g9. (Lon- 
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A Class Book of Physical Geography. By A. T. 
Simmons and E. Stenhouse. Pp. viii+436.  (Lon- 
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An Outline of the Russo-Japanese War, 1904-1905. 
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Studies in Seeds and Fruits: an Investigation with 
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Scientific Papers. By John William Strutt, Baron 
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Petrographisches Praktikum. By Dr. R. Reinisch. 
Zweiter Teil, Gesteine. Zweite Auflage. Pp. viit 
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