27^ Dr. Herschel’s Astronomical Observations 
“ compressed in the middle and very rich. The most com- 
“ pressed part of it is round and is about 2 or 2|-' in diameter, 
“ the scattered ,stars which belong to it extend to 8 or 9' in 
“ diameter, but are irregular.'"* 
Sept. 24, 1810. Large 10 feet Newtonian telescope. Space- 
penetrating power 75,82. Magnifying powers 71. 108. 171. 
220. “ The 3d of the Connoiss. is one of the globular clus- 
“ ters; very brilliant and beautiful. The compression of the 
“ stars begins to increase pretty suddenly from the outside at 
“ f of the radius, and continues gradually up to the centre, its 
diameter taking in the outside is full half of the field of the 
“ glass magnifying 171 times, which gives 4' 30"." 
Nov. 23, 1805. Large 10 feet. “ The 15th of the Con- 
“ noiss. is perfectly round, and insulated. The accumulation 
“ of the stars towards the centre is more sudden than the 13th 
“ of the Connoiss. and the scattered stars extend proportion- 
“ ally much farther. Its diameter is ^ of the field of the glass 
“ which magnifies 108 times, that is to say 4' o". It passes 
the wire in 13'', o of time which by calculation gives only 
2' n^',3, but I rely more on the estimation by the known 
“ field of view which is 24^0"; because the limits of the clus- 
ter cannot be properly fixed upon for a transit." 
Jan. 13, 1806. Large 10 feet. “ The 79th of the Connoiss. 
“ is a cluster of stars of a globular construction, and certainly 
• The 20 feet telescope, on account of the moderate weight of the mirror and the 
proportionally long wooden tube, has the great advantage that with proper precau- 
tion it may bo used in any temperature. Sometimes, however, a sudden change from 
cold to heat towards morning has put a slop to the observations of the night. The 
mirror will also preserve an excellent polish for several years; and having a second one 
ready to supply the place of that which is in use the instrument may always be ready 
for observation. 
