On the Physical Appearance of the Planet Mars during the Oppositionin 1881. 299 
December 20. 
ING, 19,—b,= 8564, Wo iP BOs, 
Definition very good; cold squalls; tube and gallery at times trembling very 
much ; interrupted by passing clouds; drawing under the most unfavourable and 
disagreeable circumstances. 
The dark spots strikingly blue; the whole of the southern dise rather bluish ; 
dise-middle orange ; central hook-like spot very dark; the canals on the middle of 
the disc very difficult to be seen. 
No, J—L.= 22°3, T.= 137 16". 
Definition good ; interrupted and afterwards stopped by clouds; cold squalls ; 
very disagreeable working. 
The dark spots very blue; northern one very dark, as well as the sp. hook-hke 
spot ; sf. a very bright spot. 
December 21. 
No, 15.—T= 326°:9. T= 10° 5”. 
Dense fog ; definition excellent; image perfectly steady, like a map. 
Markings visible up to the limb; the dark ones blue ; the disc deep orange ; the 
divisions on the middle of the disc faint and difficult; the southern spots rather 
faint, with very bright lines. 
December 22. 
No, 17 Sh= 35S, Ih= Wer 87 
Clear ; definition, however, good during very short intervals only. 
Sketch not at all in all parts-equally reliable; the sp. and n. parts best, not so 
certain the sf, ones. There is apparently a connexion between the second hook 
and the nf. sea as in sketch. 
December 26. 
No, 144,—h= S058, Wo iP BER, 
Definition good, though the image not very steady. 
The dark spots greyish-blue; the large following continent orange ; the faint 
markings on it, as well as the southern ones, very difficult. 
NO, 1G—h.= B30, I= 18)" BOR, 
Definition worse ; image very unsteady. The aperture was reduced by diaphragm 
to 27 inches diameter, by which the image was decidedly improved ; moments of 
great sharpness. 
Colours deep orange (disc-centre) and blue; the northern spots very faint ; near 
the south pole ill-defined patches which I could not make out. 
December 27. 
IN@ Wilh Baa db Se A 
Definition very good. 
The dark markings certainly blue; the np. spots on the large central continent 
