on the Rotation of the Planets , See. 1 27 
axis fliould not be inclined enough to his orbit, to occafion 
fuch a change, they may probably always blow in the fame 
direction. 
Obfervations on Mars in the year 1777* 
Twenty-feet Newtonian refleftor ; pow r er 300. 
April 8. 7I1. 30'. I obferved two fpots upon Mars, with a 
bright belt or partition between them. The belt was not very 
well defined, fee tab. VI. fig. 1 4. 
9 h. 3c/. The fpots are advanced, and more fpotted parts 
are vifible, fig. 15. 
1 oh. The revolution of Mars on his axis is now very 
evident, fig. 16. 
April 17. Ten-feet Newtonian reflector; power about 
21 1. 7 h. 5 c/. Mars appeared as in fig. 17. At a and b 
there were two bright fpots, fo luminous that they feemed to 
project beyond the dilk. At c and d there were two very dark 
fpots, joined by a leffer black line in the middle, which 
however was eroded at e and fby a very faint whitifh partition. 
April 26. Ten- feet refle&or ; power 21 1. 
9 h. The lpots on the planet are very faint, and much 
about as in fig. 18. 
April 27. Ten- feet refle£lor ; power 324. 
8h. 40'. The evening very fine : my telefcope in compleat 
order. The fpots as in fig. 19. 
Obfervations 
