1866. | Mining and Metallurgy. 115 
Professor Church has recently brought before the Chemical 
Society a communication, entitled “Chemical Researches on some 
New and Rare Cornish Minerals.” Hydrated Cerous Phosphate is 
a new mineral found by Mr. Talling, of Lostwithiel, some time ago. 
It occurs in a copper lode on quartz and killas. The general lustre 
of the mineral is vitreous; but the conspicuousness of the end-faces 
with a brilliant pearly lustre causes the general aspect of the grouped 
erystals to be splendent. The crystals are doubly refractive, but no 
specimen has yet been obtained capable of affording indications as to 
the number and direction of the optic axes. For the same reason 
they have not yet been examined as to the presence or absence of 
pleochroism. ‘The colour of the mineral is a pale smoky grey, with 
a faint tinge of flesh red; the streak and powder are white. The 
hardness of the mineral slightly exceeds 3; it distinctly abrades a 
cleavage surface of calcite. The density has not been determined 
with accuracy, but it is about 3°14. 
Professor Church’s analyses give the following as the mean per- 
centages :— 
IDS Ste Wilh OR See gn fee eA APR BEET 1 y 
STs AN a aie tg Renal net ee lait 
Poh eat ke, Cav ashy a iss y tage 
RGU abet Garg. el! aninetaedeg ote 88 
100-70 
As Professor Church says, “The occurrence of a British mineral 
rich in Cerium is, of course, of considerable interest, but the complete 
novelty of the species, as a hydrated phosphate of the metal, attracts 
particular attention, the known phosphates, cryptolite, monazite, &c., 
bemg when quite unaltered and pure completely anhydrous.” 
Mr. Talling supplied Professor Church with a mass of quartz 
erystals mixed with iron and copper Pyrites, partly covered with 
Childrenite, and containing, moreover, in numerous cavities and 
fissures a light and soft white powder. This powder was found to 
contain lime, alumina, phosphoric acid, and water, together with a 
trace of iron. The experimental percentages obtained by analysis 
were :— 
Ca" O = : - 36°27 
PEO e e ° e . . 22 40 
aioe wae, LOY OMe eon aaa 
H, O 12 00 
101-03 
The only known mineral phosphate resembling the present is 
one examined by Damour in 18538, and believed by him to be a 
hydrous phosphate of alumina and lime. Damour’s phosphate was 
found in the Diamond Sands of Bahia. The present mineral was 
obtained from near Tavistock, Devonshire. 
“ Bayldonite” is the name proposed by Professor Church for a new 
12 
