304 
MINERALOGY: G. P. MERRILL 
yielded no satisfactory returns. As a last resort a 12-gram fragment of 
the Alfianello stone was submitted to Dr. Whitfield with the request 
that it be pulverized, and, after removal of the metallic portion, boiled 
in water to remove any possible oldhamite or its alteration products, 
and the residue then boiled in dilute hydrochloric acid. Disregarding 
as a matter of necessity the iron and magnesia which might come from 
the olivine, the results obtained were as follows: The water solution 
yielded 0.03% CaO and 0.013% S, the equivalent of 0.030% CaS, or 
oldhamite. The acid solution yielded 0.344% CaO and 0.08% P2O5, 
with traces of alumina. 
Satisfactory results from such tests could scarcely be anticipated but 
are nevertheless not without interest. It will be recalled that the ratio 
of CaO to P2O5 in francoHte as given by Schaller^ is 10 to 3. The results 
obtained by Whitfield by the method described were 9 to 2. 
The accompanying figures, drawn free hand, directly from the thin 
sections, will serve to give an idea of the general appearance and optical 
properties of the mineral. No attempt has been made to outline other 
of the constituents excepting where noted as enclosures. The actual 
size of the largest forms, as those of Alfianello and Rich Mountain (figs. 
1 and 2), is not above 0.5 mm. in diameter. In figure 1, from a slide 
of the Alfianello stone, the mineral in question, left colorless and un- 
shaded, is traversed by wavy cracks or cleavage lines extending rom 
the upper right to the lower left. The dotted areas are olivine and 
those with broken parallel lines at the right are enstatite. The com- 
pletely black are metal and metallic sulphide. In the upper portion the 
mineral reaches its maximum extinction n the position indicated by the 
cross. In the lower right, which remains almost completely dark dur- 
ing an entire revolution of the stage, there appears an indistinct, slightly 
curved black bar, indicating the emergence of an optic axis of a biaxial 
mineral. 
Figure 2, from a sKde of the Rich Mountain stone, shows Hkewise a 
characteristic occurrence, with near the center an enclosure of olivine 
and other scattered enclosures of the same mineral and metallic par- 
ticles. The entire area extinguishes as a unit and in the position indi- 
cated by the cross, though the lower portion shows indications of two 
cleavages and an indistinct black brush sweeps across the field as the 
stage is revolved between crossed nicols with the occular removed. 
Figures 3 and 4 show the same mineral in the Pultusk and Dhurm- 
sala stones, respectively. The position of maximum extinction is again 
shown by the black cross. In figure 4, which extinguishes as a unit, 
two easy but interrupted cleavages are very evident at the left and bot- 
