251 
THE TOTAL SOLAR ECLIPSE OF 
JANUARY, 1898, 
ALS VISIBLE IU INDIA, 
BY 
CAPTAIN E. H. HILLS, R.E. 
A Lecture delivered at the Royal Artillery Institution, Woolwich, Thursday, 11th March, 1897) 
Colonel H. S. S. W atkin, C.B,, in the Chair. 
This lecture naturally divides itself into three portions. In the first 
part I shall speak, as briefly as possible,.of what is known of the 
physical constitution of the sun. The second portion will be devoted 
to a description of the observations that we endeavour to make 
during a total eclipse, with particular reference to those observations 
which are made by astronomers equipped with the best modern instru¬ 
ments, and in the third part I shall speak of the work that can be 
done by amateur observers, or those not provided with expensive instru¬ 
ments, with special reference to the eclipse of 1898, January 22, as 
visible in India. 
In order to examine with any success into the physical condition of 
the sun we must make use of that invaluable instrument the spectro¬ 
scope, which, as you doubtless know, is an instrument for dissecting 
and analysing a ray of light, by which means we are enabled to deter¬ 
mine the character of the source from which it emanates. If we do 
this with the sun and pass a narrow beam of its light into the spectro¬ 
scope, we shall find that the beam, after passing through the prism or 
other dispersing arrangement, is spread out into a spectrum or baud 
of prismatic colours. The groundwork of this spectrum, or the 
bright band of colour, arises from the decomposition by the spectro¬ 
scope of the white light which emanates from that portion of the sun 
which has been called the photosphere. Superimposed upon this 
band we see a number of fine dark lines, called the Fraunhofer 
lines from the name of their discoverer. 
The origin of these lines is as follows :—Above the photosphere of 
the sun is a region where there are a large number of metallic and other 
vapours, volatilized by the intense heat of the solar surface. If such a 
mass of vapour were examined by the spectroscope we should get, not 
6 YOL. XXIY. 34 
