on the Rotation of the Planets , &c. 127 
s ' axis fhould 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 refleflor ; power 300. 
April 8. 7I1. 3d'. 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. 14. 
9 h. 30'. The fpots are advanced, and more fpotted parts 
are vifible, fig. 15. 
10 h. The revolution of Mars on his axis is now very 
evident, fig. 16. 
April 17. Ten-feet Newtonian refle&or; power about 
21 1. 7 h. 50'. Mars appeared as in fig, 17. At a and h 
there were two bright fpots, fo luminous that they feemed to 
project beyond the difk. 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 f by a very faint whitifh partition. 
April 26. Ten-feet refledlor ; power 211. 
9I1. 5'. The fpots on the planet are very faint, and much 
about as in fig. 18. 
April 27. Ten-feet refiedlor ; power 324. 
8 h. 40b The evening very fine : my telefcope in compleat 
order. The fpots as in fig. 1 9, 
Obfervations- 
