TOTAL SOLAR ECLIPSE OE AUGUST 9, 1896. 
13 
Exposures for 9-inch Prismatic Camera. ' 
Number. 
Expo.sure. 
Time. 
Remarks. 
1 
Instantaneous 
10 seconds before 
totality 
Totality begins. Wait signal. 
2 
105 
3 
10 seconds 
10.3-93 
■ 
4 
5 „ 
88-83 
Clironiospliere disappears. | 
5 
10 „ 
81-71 
i 
6 . 
30 ,, 
69-39 
1 
7 
5 „ 
34-29 
' 
8 
10 „ 
27-17 
Cbromospbere reappears. 
9 
Instantaneous 
15 
10 
. 
I 
25 seconds 
10 seconds before 
totality to 15 
seconds after 
Dropping plate. 
In workino- the instrument Dr. Lockyer had five assistants. Midshipman Fitz- 
O 
WILLIAMS was in charge of the siderostat, to attend to clock-winding’, &c. ; Midship¬ 
man Bruce acted as special timekeeper to note the times by a deck watch at which 
each plate was exposed and to announce the termination of the longer exposures ; 
Shipwright P. Sullivan stood by the prism to remove the cap at a signal from 
Dr. Lockyer and to replace it when Midshipman Bruce gave the signal “ over ; 
Able Seamen H. Froud and A. Woollard respectively handed the dark slides to 
Dr. Lockyer and replaced them in the box from which they had been taken. 
The Intecjrating Spectroscope. 
This Instrument vras intrusted to Lieutenant Martin, Pt.N. 
The dispersive parts of the integrating’ spectroscope consisted of two dense flint 
glass prisms of 60°, having an effective aperture of very nearly 3 Inches. As colli¬ 
mator, a 4-inch Cooke object-glass (Tattlor’s patent triplet) of 72 inches focus was 
employed, while the camera was fitted wdth a portrait lens of 19 inches focus. The 
optical parts were mounted on a board 7 feet by 2 feet 6 inches. This wms hinged to 
another board of the same size, which was to serve as a base, and the boards could be 
inclined at an angle equal to the sun’s altitude by the use of blocks. 
The base rested upon loaded packing cases which were carefully levelled with 
cement upon a solid rocky foundation. As a siderostat was not available for use with 
this instrument, a simple arrangement was provided for keeping the collimator 
approximately directed to the centre of the dark moon during totality. A 2-inch 
object-glass of 30 inches focus was fixed to the inclined board so as to throw an image 
of the sun on the centre of a small screen when the collimator was pointed at the sun. 
The whole spectroscope could be moved in azimuth by means of a milled headed 
