11 
Form. 
Angle. 
Calculated. 
Found. 
Gmelin. 
P 
A 
125°45' 
125°40' 
125°48' 
B 
125°18 / 
125°29' 
125°18' 
C 
81°1P 
OO 
r— 1 
O 
O 
OO 
n 
A 
88°39' 
88°34 / 
B 
137°43' 
137°40' 
ooP 
W 
89°33' 
89°25' 
89°22' & 89°36' 
Poo 
W 
62° 9' 
62° 3' 
62°12' 
Silver Dithionate — Ag 2 S 2 0 6 2Aq. — forms, according to 
Watts, right-rhombic prisms, isomorphous with sodium 
dithionate. 
Gmelin 
gives some 
measurements. 
I find the 
axes to be 
a:b :c = 
0-9884:1*0: 
0-5811, and the forms Poo , 
P, CO P, pi, 
co Poo , oo Poo ; the type is very short prismatic. 
Form. 
Angle. 
Calculated. 
Found. 
Gmelin. 
P 
A 
126°47' 
126°5r 
127° 
B 
126° 6' 
125°55' 
126° 
C 
79° 9' 
79° 8' 
79°10' 
PI 
A 
89°54' 
89°58' 
90°12' 
C 
104°58' 
104°52' 
ooP 
w 
89°20' 
89°22' 
89° 8' 
Poo 
w 
60°54' 
61° V 
Silver Sodium Dithionate — (AgNa) 2 S 2 0 6 2Aq — is, accord- 
ing to Watts, “ apparently isomorphous with the component 
salts/' I find it to be rhombic with the axes a:b:c = 
09813 : l’OOOO : 0*5856, and the forms Pco , P, oo Poo , oo P, 
00 Pco ; the dome is developed so much as to make the 
crystals horizontally prismatic, the prism is only slightly 
developed, and the pyramid P J does not occur. Watts also 
says, it “exhibits very distinct cleavage;" this cleavage plane 
1 find to be oo P, and I also find that the sodium and the 
silver dithionates exhibit very distinctly this cleavage. 
Form. 
Angle. 
Calculated. 
Found. 
P 
B 
125 o 30' 
125°23' 
C 
79°48' 
79°46' 
00 P 
w 
88°55' 
89° 1' 
Poo 
w 
61°39' 
61°4P 
This sample contains % Ag. 32.0 
AgNaS 2 0 6 2Aq requires % Ag. 33.00 
