about forty tons. As each plate covers a ‘region 10° 
square, every part of the sky has been photographed, 
on the average, a hundred times. This work is now 
supplemented by two small Cooke anastigmat ‘lenses, 
each having a. field 30° square. The number of plates 
taken with these two instruments are nine thousand 
and fourteen thousand respectively. The exposures 
with the larger instruments are, in general, ten 
minutes, showing stars of the thirteenth magnitude. 
The exposures with the smaller instruments are one 
hour, showing stars of the eleventh magnitude. A con- 
tinuous history of the sky is thus furnished from 
which the magnitude and position of any stellar 
object of sufficient brightness can be determined for 
a large number of nights during the last quarter of a 
century. A striking illustration of the value of this 
collection occurred when the planet Eros was dis- 
covered in 1898. It appeared that this object was 
nearer the earth in 1894 than would occur again for 
thirty-five years. An examination of the photographs 
showed its presence on twenty-three plates, and from 
their positions, the parallax of the sun and mass of 
the earth were determined with an accuracy equal to 
that of any of the methods previously used, and on 
which an enormous amount of time and money had 
been spent. 
For many years the Kiel and Harvard Observa- 
tories have served as distributing centres of astro- 
nomical discoveries and observations in Europe and 
America, respectively. The last new star which is 
known to have appeared, Nova Geminorum No. 2, 
was discovered by Enebo at Dombass, Norway, on 
Tuesday, March 13, 1912. The cable message was 
received at Cambridge on Wednesday morning, and 
the star was observed at several American observa- 
tories the next evening, or the night following its 
discovery. An examination of the Harvard photo- 
graphs showed that two plates, had been taken on the 
preceding Sunday, March 11, on which no trace of the 
nova was visible, and two on Monday, March 12, 
showing it of nearly its full brightness. Photographs 
taken on Wednesday compared with those obtained 
a few days later showed the wonderful change in 
its spectrum, from the solar type with dark lines, to 
the typical spectrum of a nova with bright lines. 
There is no department of astronomy which is now 
receiving greater attention than the study of the spec- 
tra of the stars. Dr. Henry Draper was the first to 
photograph the lines in a stellar spectrum, although 
Sir William Huggins had already. obtained a mark 
from the spectrum of Sirius, and later was the first 
to publish his results in successfully photographing 
stellar spectra. The untimely death of. Dr. Draper 
in the midst of his work led to the establishment at 
Harvard of the Henry Draper Memorial. For nearly 
thirty years Mrs. Draper has maintained an active 
interest in this work. By placing a large prism over 
the objective of a telescope, the light of all the brighter 
stars in the field are spread out into spectra, so that 
instead of photographing the spectrum of one star 
at a time, as with a slit spectroscope, as many as a 
thousand have sometimes been taken on a single 
plate. Such photographs, covering the entire sky, 
have been taken with the two 8-in. doublets already 
mentioned. A study of the spectra thus obtained 
enabled Mrs. Fleming to discover many hundred 
objects the spectra of which are peculiar.. Among 
them may be mentioned ten of the nineteen new stars 
known to have appeared during the years in which 
she was engaged in this work, while five of the 
others were also found at Harvard by other observers. 
She discovered more than two hundred variable stars, 
ninety-oné out of the 108 stars of the very peculiar 
fifth type, and showed that these objects occurred 
NO, 2211, VOL. 92] 
NATURE 
c 
[FEBRUARY 12, 1914: 
only ‘very near the central line of the Milky Way. 
During the last two or three years a great demand 
has arisen for the class of spectrum of large numbers 
of stars. The Harvard photographs show the class 
of spectrum of nearly two hundred thousand. stars. 
Miss Cannon has, accordingly, undertaken to prepare 
a catalogue of these objects, with the result that she 
has already classified about one hundred and fifteen 
thousand spectra, covering more than one-half of the 
sky. The work is progressing at the rate of five 
thousand stars monthly, and the results will fill seven 
of the large quarto Annals of the Harvard Observa- 
tory. The organisation of this work has required 
the most careful application of the principles of 
“scientific management.” Ai: 
One of the most important results derived from the 
Harvard photographs was the discovery that in cer- 
tain spectra the lines were alternately double and 
single. This, and the discovery by Vogel at Potsdam 
that the lines of the variable star Algol continually 
changed their position, revealed the existence of 
spectroscopic binaries. No department of astronomy 
is receiving more attention, at the present time, than 
these objects, and in general the motion of the stars 
in the line of sight. The Lick, Yerkes, Greenwich, 
Potsdam, Bonn, and Ottawa Observatories are only 
a portion of those directing a large part of their 
energy to this subject. i 
One of the most important generalisations of recent 
times is the discovery by Prof. Campbell that the 
The proper motion of a star was similarly found by 
the late Lewis Boss to be dependent on the same 
quantity. ia 
In conclusion, the United States has attained an 
enviable position in the newer departments of astro- 
nomy. Can this be maintained? In Europe, 
especially in Germany, observatories and instruments 
of the highest grade are now being constructed, the 
Government furnishing appliances with the most 
liberal hand. Perhaps the most promising sign for 
the future is the friendly cooperation of American 
astronomers, which has never been more marked than 
at the present time. : 
The possibilities of work are now greater than ever 
before. A small fraction of the effort sxpended in 
teaching science, if devoted to its extension and pro- 
gress, would fulfil the objects of the American Asso- 
ciation for the Advancement of Science. : : 
UNIVERSITY AND EDUCATIONAL © 
INTELLIGENCE. 
CamBripGE.—A matter about which there is con- 
siderable divergence of opinion will come up for settle- 
ment this term. The Special Board for Medicine 
wishes to apply to the Board of Agriculture for a 
grant towards the medical department. Such grants 
are now commonly being made to the various medical 
schools in other parts of England, but Government 
grants mean Government control, and certain mem- 
bers of the Senate are apprehensive that Government 
control would mean an undue interference with the 
liberty of the University. On the other hand, similar 
grants, with the implied control, have already been 
accepted by the Cambridge School of Agriculture and 
by the department of astrophysics. The returns from 
the various colleges show that there are 330. medical 
students now in residence in the University. An 
examination of the figures relating to the grant made 
to three of the London medical schools for their full 
time students affords evidence that the grant is about 
14l, per annum a student. Taking these two figures, 
| it may be calculated that the Cambridge Medical School 
velocity of a star depends upon its class of spectrum. 
Oe 
