NATURE 
[JUNE 27, 1912 
432 
was summarised in our issue of March 28 (p. 98). 
In addition to the above papers, the volume contains 
a report of the proceedings of the Birmingham Branch 
of the institute, and a valuable series of abstracts of 
papers. 
A sECOND article dealing with Messrs. Whiteley’s 
new premises appears in The Builder for June 2t. 
In accordance with modern ideas, old-fashioned 
methods of sweeping and dusting have been aban- 
doned in favour of vacuum cleaning apparatus, con- 
structed by the Vacuum Engineering Company, Ltd., 
of London. There are three powerful vacuum 
machines, each consisting of a turbine vacuum 
cleaner having a normal capacity of 800 and a maxi- 
mum capacity of 1800 cubic feet of air per minute. 
A centrifugal separator collects the dust in a tank, 
and the air passes away through an exhaust outlet 
18 in. in diameter. The main risers are 4 in. in 
diameter, and have an aggregate length of about 
1000 ft.; the horizontal pipes are 5 in. in diameter 
with an aggregate length of 1200 ft.; all these pipes | 
are of mild steel, of specially smooth interior. There 
are 104 inlets, to which hose-pipes may be attached; 
these are distributed at convenient points on the walls 
of the building. The hose-pipes are of 2-in. internal 
diameter, and from twelve to twenty-four of them 
may be in use simultaneously. 
Mr. Joun Murray now publishes in this country, 
at 6s. net, Dr. L. O. Howard’s book, ‘‘The House | 
Fly—Disease Carrier: an Account of its Dangerous | 
Activities and of the Means of Destroying it,’’ which 
was published by the Frederick A. Stokes Co. of New 
York in 1911. The book was reviewed at length in 
these columns on January 11 last (vol. Ixxxviii., 
P- 345): 
Mr. W. H. Hartine, Finsbury Pavement, London, 
has issued No. III. of his sectional catalogue of 
mathematical, drawing, and surveying instruments. 
This section gives exhaustive particulars and the 
prices of numerous forms of scales, pantographs, 
planimeters, and other instruments in constant use by 
draughtsmen, surveyors and others. 
Mr. S. A. McDowatt’s “Laboratory Notebook of 
Physics,” which was reviewed in the issue of NATURE 
of May 30 (vol. Ixxxix., p. 317), can now be obtained 
from Messrs. J. M. Dent and Sons, Ltd., in four 
separate parts. The parts deal respectively with 
measurement and hydrostatics, heat, light, and mag- 
netism and electricity. The price of part i. is nine- 
pence net, and of each of the others one shilling net. 
Messrs. J. M. Dent anp Sons, Lrp., have added 
to their ‘‘ Educational Journey ”’ series, a pamphlet of 
sixty-four pages, by Mr. G. H. Green, entitled a 
“Nature-study Note-book,” the price of which is 6d. 
The booklet is profusely illustrated, and is intended 
to be of service to young pupils who are fortunate 
enough to be taken by their teachers for school 
journeys—an educational expedient which is for- 
tunately becoming increasingly common in_ this 
country. 
NO. 2226, VoL. 89] 
OUR ASTRONOMICAL COLUMN. 
THe SpecrruM oF Nova GEminorum No. 2.—Fur- 
ther particulars of the reported discovery of radium, 
uranium, and emanation radiations in the spectrum 
of Nova Geminorum are communicated to No. 4582 of 
the Astronomische Nachrichten by Prof. Kistner. 
The plates were taken and reduced by Dr. H. 
Giebeler, who discusses the peculiar variations of the 
structure of the several emission and absorption bands 
of hydrogen, &c., and gives three curves showing the 
relative intensities of the bands and the continuous 
spectrum on March 19, 26, and 27 respectively. 
It is among the numerous fine, so-called absorption 
lines, to which so many origins and so many different 
radial-velocity shifts have been ascribed, that Dr. 
Giebeler finds the coincidences with lines due to the 
radium group of elements. Taking all the known 
radium spark lines, from a table given in the manu- 
script for the sixth volume of Prof. Kayser’s ‘t Hand- 
buch,”’ twelve in all, he finds a line approximately 
| coincident with each of them in the nova spectrum ; 
the differences range from —166 to +132 A. 
Although eight negatives were measured, four of these 
nova lines were found to occur once only, and each 
of them on a different negative taken on another 
date; two others, also occurring once only, are found 
on a fifth negative. Only three lines were found to 
occur on as many as three negatives, and, while the 
intensities of the laboratory lines range from 50 to 2, 
the intensities of these three lines are 2, 4, and 2 
respectively. The mean wave-length of the nova line 
attributed to the strongest radium line (A=4340°83) is 
434165, a position very near to the dark reversal of 
Hy. 
Of six arc lines of uranium four are represented 
in the spark and four in the nova spectrum, but of 
the four spark lines only two appear in the nova, 
and the only line, 44472°50, which, from the laboratory 
data, may be an enhanced line, is not represented in 
the nova at all, unless one accepts the line shown on 
one negative at A447188; but Dr. Giebeler assigns 
this to helium. The four lines attributed to uranium 
occur on four different negatives, the only one to occur 
twice being the 4341 line already attributed to radium. 
Of the ten lines shown in the Giessler-tube spec- 
trum of the emanation, six are represented in the 
nova spectrum with differences varying between 
+0°64 and —o's51 A, the intensities in the laboratory 
spectrum being 20, 5, 10, 10, 4, and 4 respectively; 
the corresponding intensities of the lines not repre- 
sented are 6, 15, 10, and 7 respectively. Of the six 
lines approximating to coincidence, only two are 
shown on any one negative (April 2); each of the 
other four appears once only, on four cifferent dates 
| ranging from March 16-19. 
From the above brief summary it will be seen that 
the presence of these radio-active elements in the nova 
should be accepted with great reserve until more con- 
clusive evidence is forthcoming. 
A CHANGEABLE RED Star, WX Cyani.—In October, 
1903, Prof. Wolf announced the discovery of a prob- 
able new star, which subsequently proved to be 
BD+37° 3876, and Prof. Barnard examined it with 
the 4o-in. Yerkes refractor. He re-observed it last 
summer, and now communicates the results of his 
measures in No. 4581 of the Astronomische Nach- 
richten. The object shows marked fluctuations in 
colour, at times appearing a very deep red, and varies 
in magnitude. It is evidently of special interest, and 
Prof. Barnard gives a scaled chart showing the 
neighbouring reference stars used by him; the position, 
foretomro, is a=20h. memeemaioss., O—370Nero! 
Tsao! 
Ore, 
