Jury 18, 1912] 
NATURE 
511 
extensive experiments with plants, may prove to be | 
of great scientific importance. In the second paper 
the author indicates some of the recent reactions of 
modern palzobotany upon the phylogeny of the higher 
plants, and points out that the great problem of 
palzeobotany to-day is the history of the Angiosperms. 
Tue annual reports of the West Indian Department 
of Agriculture are, as usual, very satisfactory, show- 
ing continued progress in various directions. The 
activities of the staff cover a wide range; plants are 
distributed from the Botanical Gardens; instructors 
are sent out to show the best methods of cultivation ; 
in some islands prizes are awarded for the best hold- 
ing; and investigations are . undertaken of the 
numerous insect and fungoid pests. Large importa- 
tions of Hevea rubber seeds were made at Grenada 
with the view of diversifying the agriculture; im- 
provements have been effected in the limejuice in 
Dominica; Para rubber (but not Manicoba rubber) is 
proving successful in St. Lucia, while in spite of a 
bad season, the output of limes from the Virgin 
Islands was higher than in previous years, and the 
value of the cotton crop was increased. 
AN investigation has been made by Prof. Ewart, of | 
Melbourne, on bitter pit in apples, the results of 
which are published in the Proceedings of the Royal 
Society of Victoria, vol. xxiv., part 2. He concludes 
that bitter pit is not a disease, but a symptom of local 
poisoning produced in the sensitive pulp cells of the 
apple, which may be induced by a variety of poisons. 
In some cases poisonous sprays may be the cause, 
and the trouble appears to be more prevalent in 
sprayed orchards than in those that have never been 
sprayed or had poison applied to the soil. But this 
is not an invariable rule, and it will be interesting to 
ascertain what poisons are at work in unsprayed 
orchards. During the course of the work it is shown 
that the cells of the apple fruit are extraordinarily 
sensitive to traces of poison. 
In a note in our issue of May 16 on the proposed 
substitution of electric for gas lighting in the House 
of Commons, we expressed doubts as to the necessity 
for placing the lights behind amber-coloured glass in 
order to guard against the effects of ultra-violet light 
on the eye. Our view is confirmed by a paper by 
Dr. Louis Bell which appears in the May number of 
the Proceedings of the American Academy of Arts 
and Sciences, and records the results of a series of 
measurements of the amounts of ultra-violet light 
sent out by various artificial lights per candle-power. 
The quartz mercury arc in its diffusing globe sends 
out least, and the carbon are enclosed in quartz 
most, ultra-violet rays per candle-power, but the 
numbers for these artificial sources are far exceeded 
by that for daylight. In these circumstances it seems 
unnecessary within buildings to protect eyes which 
prove themselves hardy enough in the daylight out- 
side. 
Tue value obtained by Prof. Joly twenty years ago 
for the specific heat of air at constant volume was for 
many years regarded as too high compared with the 
values for the specific heat at constant pressure 
NO. 2229, vor. 89| 
| of a paper by Drs. 
obtained by Regnault and Wiedemann. Three years 
ago Dr. Swann published results for. the latter 
quantity, determined by the continuous-flow method, 
which were higher than those obtained previously, and 
fitted in well with the observations of Joly. A copy 
Scheel and Heuse, of the 
Reichsanstalt, which appeared in a recent number of 
the Annalen der Physik, has reached us, which con- 
firms Swann’s result, and gives values of the specific 
heat of air down to —183° C. The method used was 
that of continuous flow, and the results in gram 
degrees at 15° C. per gram degree are as follows :— 
at 20° ©., 0-241; at —78° C,, 0-243; and at —183° € 
0-253. 
Messrs. A. F. Host anp Son, of Copenhagen, 
announce the early publication of vol. i. of the “ Re- 
port on the Danish Oceanographical Expeditions, 
1g08—1910, to the Mediterranean and Adjacent Seas.”’ 
Dr. Johs. Schmidt, the leader of the expeditions, will 
contribute an introduction, and other chapters will 
deal respectively with hydrographical observations, 
hydrography of the Mediterranean and adjacent 
waters (by J. N. Nielsen), exact determination of the 
chlorine in some samples of sea water from the 
Mediterranean (by H. Bjorn-Andersen), determination 
of the quantity of oxygen in sea water (by S. 
Palitzsch), the amount of oxygen in the water of the 
Mediterranean (by J. P. Jacobsen), measurement of 
the hydrogen ion concentration in sea water (by S. 
Palitzsch), the deposits of the sea-bottom (by O. B. 
Boggild). Other volumes dealing with biological 
matters will be issued later. : 
Errata.—By a regrettable oversight the heading of 
the article in Narure of July 11 re the Provisional 
Programme of Sections of the forthcoming meeting 
of the British Association appeared as ‘‘ The Sheffield 
Meeting of the British Association.” The meeting 
will, of course, be held at Dundee, as is stated in the 
article.—In the letter of Prof. MacBride on ‘ Hybrid 
Sea-urchins,” in Nature of July 4, p. 450, col. i., for 
| Echinus nuharis read Echinus miliaris. 
OUR ASTRONOMICAL COLUMN. 
Tue Masses or Dous_e Stars.—The following in- 
teresting figures concerning the masses of pairs of 
double stars are published by Dr. Doberck in No. 4583 
of the Astronomische Nachrichten; the spectral type 
(Harvard) is shown in brackets :— Cassiopeia (F8), 
0°87; 40 uo? Eridani (G5), 0°43; Sirius (A), 3°26; Castor 
(A), 72°19; 2.3121, 3719; 7 Virginis (FE), 8'09; « 
Centauri (G, Ks), 199; ¢ Herculis (G), 0°73; 4° Her- 
culis (G5), rir; 70 p Ophiuchi (K.), 2°58; and 85 
Pegasi (G), 3'07. Excluding Castor and = 3121, the 
former because the orbit is uncertain, and the latter 
because the parallax is too small, the mean value is 
2'46, and as this includes both stars of the pair, the 
average mass of a single star is approximately equal 
to that of the solar system, which is taken as unity. 
The data are, as yet, too meagre to allow of any 
attempt to correlate average mass and spectral type. 
SoLtar PROMINENCES IN 1911.—According to Prof. 
Riccd’s annual summary, published in No. 5, vol i. 
(and series), of the Memorie della Societa degh Spettro- 
scopisti Italiani, the frequency, size, and magnificence 
of the solar prominences observed at Catania in 1911 
were all considerably less than in 1910. The mean 
