40 Brush and Dana—Feairfield County Minerals. 
an acid solution by means of ammonium carbonate, evaporat- 
ing the filtrate to dryness, igniting to drive off ammonium 
salts. e residue was taken up in water, Saco hydroxide 
added to precipitate any phosphoric acid or manganese which 
might have remained in solution, the excess of barium sepa- 
rated and the sodium weighed as ‘sodium chloride. Care was 
taken to carry on the eva eeuices in platinum and avoid 
contact with glass as muc possible. Water was deter- 
mined by igniting in a B anarhan ee tube ina gas snes 
the water being collected in a chloride of calcium tu 
Two analyses gave: 
Relative number of atoms calculated 
I, Il. Mean. from the mean. 
Li 2 31°10 30°99 31°05 "219 A ip 
A1O, 21°99 22-40 22°19 -216 “99 ‘i 
FeO 4-42 7°39. 7-40 "103 | 
MnO 23°47 23°56 23°51 “Sad. i j 
CaO 54 54 64. 10, 2°05 - 
Na,O “38 33 33 005] 
H,O 15°66 15°54 15°60 “866 3°95 4: 
10051 100-75 100-62 
The ratio P,O, : AIO, : RO: H,O=1:1:2: 4 corres “ to 
the empirical tpaala R, AIP yO; >; 48. O, which may be writ- 
ten AIP,O,+2H, RO, +2aq. The analogy in the Bains 
tion of eosphorite to that of childrenite oi ee however, 
that the better way of writing the formula 
R,P,0 H,RO, 
i AIP;O, +} Hi AlO, 1494 
In the formula R corresponds to Mn and Fe with small quan- 
tities of Ca and Na, ; the ratio for Mn: Fe+Ca+Na,=3:1, 
and for Mn: Fe=10:3; for the last ratio the above formula 
requires :— 
Eosphi drenit drenite, analyzed 
Calculated from Res socuinia. “= Pieter — Church. 
?,0; 30°93 28°92 30°65 
Al0, 22°35 14°44 a 15°85 
‘ eO,; 3°51 
FeO 7-24 30°68 Fe02 3-45 
MnO 23°80 9°07 TIA 
MgO O14 1°03 
H,0O 15°68 16°98 17°10 
100°00 G.=3°134 100°23 G.=3-247 99°33 G.=3°22 
The identity between the sh as form of poepnrte and 
that of childrenite has been pointed out in a preceding para- 
graph, and the male, between them in chemical composition, 
and at the same time the wide difference, will be seen from the 
above. The ratios obtained from the analyses of Rammelsberg 
and Church for the childrenite from Tavistock and that of eos- 
phorite are as follows :— 
