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Dec. 14, 1882] 
NATURE 
165 
reasonably available, for adding to our knowledge of the subject, 
should be neglected. And, therefore, without committing 
myself or the Society to the support of any particular proposal 
or expedition, I think it may be fairly claimed as a prim facie 
duty on the part of the present generation to obtain as many 
faithful records of the various phenomena occurring daring solar 
eclipses as possible. 
From a discussion of the meridian observations of Mars made 
during the favourable opposition of 1877, at Washington, 
Leiden, Melbourne, Sydney, and the Cape, Prof, Eastman has 
deduced the value 8”°953 for the solar parallax—a value which, 
though considerably larger than any of those found by other 
methods, agrees closely with that obtained by Mr. Downing, in 
1879, from the meridian observations of Mars at Leiden and 
Melbourne, as well as with the values found from similar observa- 
tions in 1862. In this investigation, Prof. Eastman rejects the 
observations at Cambridge, United States, as they were made in 
a slightly different manner, and gives (in combination with 
Melbourne) a very large value for the solar parallax, viz., 9"138. 
The detailed account of the British Observations of the Transit 
of Venus, 1874, was published at the beginning of the year, and 
the observations of the transit made at colonial observatories 
have been recently printed in the Memoirs of the Royal 
Astronomical Society. 
The Transit of Mercury last November was well observed in 
Australia and other places, and the results are of speciai interest 
in connection with the late Transit of Venus. The discord- 
ances in the times of internal contact recorded by different 
observers seem to show that such observations are subject to 
much uncertainty. 
An important memoir on astronomical refraction has been 
lately published by M, Radau, who, afver a di-cussion and com- 
parison of previous theories, gives formule and tables for 
refraction, in which allowance may be made for difference in the 
rate of decrease of temperature with the height above the earth’s 
surface at different seasons of the year. M. Radau also dis- 
cusses the case in which the surfaces of equal temperature in the 
atmosphere are inclined to the earth’s surface. 
A new map of the solar spectrum, containing a much: larger 
number of lines than are shown in Angstrom’s classical normal 
spectrum, has been published by Prof. Vogel in the publications 
of the new Astrophysical Observatory at Potsdam. In this 
work Prof, Vogel has bestowed great care on estimates of the ! 
breadth and intensity of each line. In the same volumes are 
given the results of Prof. Spdrer’s sun-spot observations at 
Auclam from 1871 to 1879, in continuation of those for the 
years 1861 to 1870, previously published. From a comparison 
of the rotation-angles for 78 spots with the formula, Prof, 
Sporer finds that the larger deviations are always towards the 
west, indicating that a descending current has brought down with 
it the larger velocity of the higher regions of the sun’s atmos- 
phere. The law previously deduced by Prof. Spérer, that, 
about the time of minimum, spots commence to break out in 
high latitudes, and that the zone of disturbance gradually 
approaches the equator till at the minimun it coincides with it 
and dies away, to be replaced by a new zone in hizh latitudes, is 
confirmed by the recently published Auclam results, comprising 
(with Carrington’s series) two complete spot-cycles. 
In astronomical photography an important advance has been 
made by the successful application of the new processes to the 
nebulz as well as to the comets. Prof. Henry Draper and Mr, 
Common have obtained photographs of the great nebula in 
Orion, showing considerable detail, and Mr. Huggins and Prof. 
Henry Draper have succeeded in photographing its spectrum, 
Mr. Huggins finds in his photograph a very strong bright line in 
the ultra-violet at wave-length 3730, in addition to the four 
nebular lines previously discovered by hi nin the visible portion. 
Prof. H. Draper’s photographs do not show this brizht line, 
though they have faint traces of other lines in the violet, and he 
thinks that"this may be due either to thie circu stance that he had 
placed himself on a different part of the nebula or to his use of 
a refractor with glass prism, while Mr. [{ug ins used a reflector 
and Iceland spar prism. The mo-t strivinz feature of Prof, 
Draper’s photographs is perhaps the discovery of two condensed 
portions of the nebula (just preceding the Trapezium) which give 
a continuous spectrum. 
Prof. Schiaparelli has recently called attention to a peculiar 
feature on the planet Mars. In 1877 he remarked a number of 
narrow dark lines, which he called ‘‘canals,” connecting the 
dark spots or so-called ‘‘seas” of the southern and northern hemi- 
spheres. He now finds that these lines are each doubled, so that 
according to his view the equatorial regions of Mars are covered 
by a network of pairs of parallel straight lines. It is to be 
remarked that though the appearance of Mars as depicted by 
Prof. Schiaparelli differs greatly from previous representations, 
indications of these double ‘* canals” are to be found in the 
sketches of other observers. 
The two bright comets of this year possess more than usual 
interest. The bright comet discovered at Boston by Wells, on 
March 18th, was the first comet since the spectroscope was 
applied to these objects, which presented a spectrum unlike the 
hydrocarbon type common to all other comets which appeared 
since 1864. The eye observations, as well as its photographic 
spectrum (!aken by Mr. Huggins), showed an absence of the 
hydrocarbon spectrum, which was replaced by a_ brilliant 
continuous spectrum and bright lines, including those of sodium. 
In September, a very brilliant comet appeared near the sun. 
It seems to have been discovered independently by Ellery, at 
Melbourne, Finlay at the Cape. Mr. Common in this country, 
and also by Thollon and Cruls. This great comet has been 
a brilliant object in the early mornings during the past two 
months. On September 17th, an observation, apparently 
unique in the history of astronomy, was made by Mr. Gill at the 
Cape, who watched the comet right up to the sun’s limb. It 
could not, however, be detected inthe sun, and this circumstance 
of appearing neither bright nor dark when in front of the sun, 
appears to sugyest a very small substantiality, or great separation 
of the cometary matter. After perihelion it presented a magni- 
ficent appearance, having a tail 30° long, and even on October 
30th the tail covered a space greater than the mean distance of 
the earth from the sun. 
On October 9th, Prof. Schmidt discovered a nebulous object 
not far from the great comet, the orbit of which strongly suggests 
a connection in the past with the great comet. This fact is of 
more interest when the orbits of the great comet of this year, of 
Comet I, 1880, and of the well-known comet of 1843 are com- 
pared. The very near approach of the great comet to the sun 
will lead astronomers to watch with great interest for its return 
to our system, whatever may be its destiny, to fall ultimately 
into the sun, or to disappear throngh a process of gradual dis- 
integration. In the Astronomische Nachrichten, just published, 
Prof. Pickering, who has computed the elements of the orbit of 
this comet, states, ‘‘ I believe the deviation from a parabola to 
be real, although the corresponding period may be very long. 
These differences seem to indicate that the disturbance suffered 
by the comet in passing through the coronal region could not 
have been great.” 
This comet presented a spectrum similar to that of Comet 
Wells, but while receding from the sun, the bright lines of its 
spectrum became fainter, and then the usual hydrocarbon 
spectrum made its appearance. This observation, taken in 
connection with those of the previous comet, suggests a modified 
condition of an essentially similar chemical constitution. The 
phenomena would admit more easily of explanation if the 
cometary light is supposed to be due to electric discharge as it is 
well known how preferential is the electric discharge when 
several substances are present together in the gaseous form. 
Before leaving this subject, I venture to quote the following 
passage from the Odservatory, which puts in a very clear form 
the speculations now current, on the relation of the present 
great comet to that of 1880, 1843, and possibly 1668. 
“‘The physical appearance of the comet, which like that of 
1843, and unlike that of 1880, showed at first 2 decided nucleus, 
together with the intimation of a period very considerably greater 
than that of the interval from 1880, January 27, the date of peri- 
helion of the 18S0 comet, suggest that perhaps the 1843 comet 
suffered disintegration when at its nearest approach, and that the 
1880 comet was a portion of its less condensed material, whilst 
the body of the comet with the principal nucleus, suffering less 
retardation than the separated part, has taken two and a-half 
years longer to perform a revolution. The remarkable discovery 
made by Prof. Schmidt, of Athens, on October 8, of a second 
comet only 4° S. W. of the great comet, and having the same 
motion, would seem to confirm this view.” 
The scientific year now concluded has not been so fertile as its 
predecessor in the initiation of great national and international 
undertakings, neither have any of those larger enterprises which 
I took occasion to mention last year, such as the circumpolar 
observations, or the Transit of Venus Expeditions, as yet been 
brought to their final issue. Nevertheless, in some of them we 
