332 NAKRORE 

OUR ASTRONOMICAL COLUMN. 
Comer 1915a (MetiisH).—Although Mellish’s comet 
is brightening up, its large and increasing southern 
declination does not make it an easy object to observe 
in these latitudes. For the sake of those observers 
who are more favourably situated the following 
ephemeris, communicated by J. Fischer-Petersen 
(Astronomische Nachrichten, No. 4796), gives the posi- 
tions up to June 5, when the comet attains its maxi- 
mum brillianey. 
A (true) Dec, (true) Mag. 
NTL a j 
Maya2 20 es ee LOl 33042) ae omnorg 
Hi ny TG) A Po 0) TT oR 
260. 19 52. 49 «+ 43 41-9 
28 20) 15/50) eee Oe272770enne5:O 
30 2082203 0) ES SEO 
June 1 20 45 a0) eh SS sos ees) 
See 257, ... —68 Io oe 4:7 
In an appendix to No. 4800 of the Astronomische 
Nachrichten a telephone message to the Computing 
Bureau is reported from Prof. R. Schorr, stating that 
the nucleus of this comet has become divided into two 
parts, their magnitudes being 11 and 13, distance 20", 
and position angle 291°. This fact was recorded on 
photographs taken by Dr. H. Thiele with the reflecting 
telescope of the, Bergedorf Observatory. 
PHOTOGRAPHIC DETERMINATIONS OF STELLAR 
Paratitax.—With the hope of making more accurate 
determinations of stellar parallax by means of photo- 
graphy, Mr. Adriaan van Maanen has been utilising 
the 60-in. reflector of the Mount Wilson Solar Observa- 
tory for this purpose. At present he has only com- 
pleted the discussion of fine stars, and these promising 
results are briefly described in the Proceedings of the 
National Academy of Sciences (April 15, vol. i., No. 4). 
The following table gives the names of the stars, the 
parallaxes derived, the probable errors, and the number 
of exposures :— 

Star Parallax Prob. error No. of 
* By exposures 
Boss P.G.C. 96 +0-026 0-007 14 
672 —0:009 0-004 14 
1549 + 0-001 0-001 16 
2921 +0:078 0-006 Io 
3233 +0:003 0-010 12 
Mr. van Maanen states that the mean probable error 
of a parallax for the mean of thirteen exposures is not 
quite 0-006", and “if we compare this result with the 
best-known photographic determinations of parallaxes 
- it will be seen that we have gained considerably.” 
He gives a list of these best-known parallaxes showing 
the mean probable errors in each case. Thus the four 
least probable errors from this list are as follows :— 
Mean prob. No. of 
Instrument Observer error exposur:S 
= r : { Slocum f 
Yerkes (40 in.)... o7009_... +28 
(UMitchelly ss; 
Yerkes (40 in.) a dc 
Swarthmore (24 in.)... 
Yerkes (40 in.)... 
Copa aa A 
CHOI Goal 
Miller : 
OlOL3) ee. 37 
Schlesinger... 
Report OF THE KopaiKANAL AND Mapras OpsErva- 
ToRIES.—The annual report of the director, Mr. J. 
Evershed, of the Kodaikanal and Madras Observa- 
tories, for the year 1914, has just come to hand. 
Reference is made in the first place to the expedition to 
Kashmir to test the suitability of the climate for solar 
research, the result of which was recorded in this 
column on December 24 last. A long list is given of 
the instruments belonging to the observatory, which 
list includes the instruments received from the Takh- 
tasinghji Observatory at Poona. During the year a 
NOMZ3775 VOL: 95] 


[May 20, 1915 
positive on negative spectrum comparator, constructed 
by Messrs. Hilger from designs by the director, was 
received, and also a diffraction grating ruled by Ander- 
son, with ruled surface 9-7 x 12-8 em., and total number 
of lines 75,085. This grating was immediately mounted 
in the large spectrograph, and ‘‘is the most perfect 
the observatory possesses, and it is now used in all 
researches where high resolving power is required.” 
The work accomplished by the various instruments is 
next described. Under the heading of the spectro- 
heliograph it is stated that the measures made from 
‘spectroheliograms -will in future replace detailed ob- 
servation at the telescope of the position angles and 
heights of the prominences. Summaries of sun-spot 
and prominence observations are given, showing that 
the solar activity was at a minimum in 1913. Eleven 
bulletins were published during the year. The report 
of the Madras Observatory describes the time observa- 
tions and a general account of weather summary. 
The appendices contain tables of the seismic records 
at Kodaikanal and meteorological observations at both 
Kodaikanal and Madras. 
AsTRONOMY at Hampsteap.—In the year 1899 the 
Hampstead Scientific Society was promoted for the 
study and encouragement of a popular interest in 
science, and at the present time there are three special 
sections of the society, namely, astronomical, natural 
history, and photographic. The report for the past 
year gives one a good account of the activity of the 
society, but, like many other societies, the disturbing 
influence of the war has been responsible for a smaller 
output of work. During the latter part of the year the 
enforced closing of the observatory rendered any ob- 
servations impossible, but the attendance of members 
at the meetings fortunately did not suffer. The report 
of the astronomical section refers to the observational 
and theoretical work in connection with the planet 
Saturn, the new subsection of lunar detail, and the 
eclipse of the sun in August last. Brief accounts are 
given of the papers read at the meetings. 

RECENT WORK IN APPLIED BIOLOGY. 
sve recent numbers of the Journal of Economic 
Biology (vol. ix., 3, 4, 1914) contain an interest- 
ing article on the biology of sewage disposal, by 
J. W. Haigh Johnson, who points out that in sewage 
filters “‘the varying intensity of pollution between the 
crude sewage and the purified effluent would provide 
suitable conditions for the development of a range of 
organisms.”” The flora consists mostly of bacteria 
such as Bacillus coli, Zoogloea, and such fungi as 
Saprolegnia and Sporotrichum. On these feed larvze 
of small hairy flies belonging to the genus Psychoda, 
which often swarm around sewage outfalls. Enormous 
numbers of the small blue-black springtail Achorutes 
viaticus form a characteristic and interesting feature 
on the surface of the liquid. 
In the Journal of Agricultural Research, published 
by the United States Department of Agriculture, 
valuable biological papers constantly appear. In 
VOL Amie OpOnmE |) (Ge Kelly describes a new sarco- 
phagid parasite of grasshoppers. The female Sarco- 
phaga ‘strikes’? at the grasshoppers (species of 
Melanoplus and Schistocera) when flying, causing 
them to drop to the ground. She deposits tiny active 
maggots beneath the grasshopper’s hind-wing. 
Thence they crawl to the metathorax and enter the 
victim’s body through the soft cuticle at the wing- 
base. 
The same number of the Journal contains an 
account, by F. Knab and W. W. Yothers, of Toxo- 
trypana curvicauda, the ** Papaya fruit-fly,’”’ the female 
of which, by means of an ovipositor as long as her 





