222 J. M. Blake on Gay-Lussite from Nevada Territory. 
The planes observed by Phillips were J, O, 22, 17, 12, and 4; 
and the monoclinic axes, calculated from his measurements, are 
a:b:c=1:444:1:489:1; C=78°27'. Of the above- mentioned 
planes, 7? was not detected on the —- crystals, But there 
and . then appears to be made up of numerous microscopic 
plan The same was true of 17. These tw 
Sen, giving no definite reflected image of the 
sun, were approximately measured by noting | 
the: points at which ~ light was reflected with 
e€ maximum inten 
In my trials I Sonica the cleavage parallel to 
planes J perfect; parallel to O less perfect, giv- 
ing a reflected image with a strong light. Speci- 
mens in the Yale Cabinet from near Lake Ma- 
racaibo, South America, showed the same com- 
posite character of the planes; but the effloresced 
condition of the specimens prevented any exact 
comparison with them 
The following are the angles obtained: the faces are mostly 
too feebly polished to afford results nearer than a degree. The 
angles are ivi in the order in which they were obtained in 
the several zones. 
Zone Ist: J on J; 69° 25’; £ 180° 20’; J, 247°5 
Zone 2d: 12 on li, 69° 30’; os 128° 20": h, vr 50’, 179° 
40’; 12, 249° 30’; O, 304° ; li, 
Zone 3d: Ion 12, 43° 20’; 3 71°, small; J, 180° 20’; 1%, 
221° 20’; 4, 249° 40’, small. 
Zone 4th : Zon 1, 53° 10’; Z, 179° 20°, 180° 10’; 12, 281° 
20’; J, 359°, 
Zone Sth h; on }, 52° 50’; 0, 96° 10"; 1 179° 10'; 4, 231° 
16; 0, 2 
Zone eth O on 1i, 50°; 2, 101°; O, 178° 40’; 12, 228° 30’? 
; 
28 
’ The following are Phillips’s sei sting in three 
zones, on all of rie observed p lanes: 
Zone lst: I on a, 84° 25’; TL, 68° 50) 5 180°. 
Zone od: Lion 2, 85° iB 1i, 70° 30’; 0, 125° 10’; 13, 180°. 
Zone 8d: Ion 13, 42° 15; 4, 69° 55’; 1%, "110° 20’; J, 180°. 
New Haven, Ct., Jan. 1866. 
