Intelligence and Miscellaneous Articles. 79 
In Analysis I. the calcined mineral was decomposed by bisulphate 
of potash, and in Analysis II. by sulphuric acid. 
A. shows the average calculated for uncalcined mineral. 
B. the amount of oxygen :— 
I. TT. A. B. 
Hyponiobic acid.... 45°10 45°24 43°49 8:58 
PATCONIA:.:< ack 6a 0°83 a 0°80 0°21 
Tungstic acid...... 1:40 ire 1°35 0:28 
Oxide of tin...../. 0°10 Ss 0:09 0:02 
Oxide of lead...... 0°43 py 0°41 0°03 
Oxide of copper.... 0°36 4 0°35 0:07 
aU Le eS eee 33'13 3 31:90 6°35 
Protoxide of cerium. 3°82 es 3°68 0°53 
Protoxide of iron... 1°17 ee Eh 0°24 
Protoxide of uranium 4°28 a 4°12 0°49 
MCT een er Ue rs 1°95 0°55 
Magnesia........-. trace a trace 
Li i aes a 725k 7°23 hee 
ECE focsrc incre cies) | <<e en Boil 3°29 
The amount of oxygen in the acids to that in the bases is as 
1: 1:04, from which we may deduce the formula 3 RO+ Nb? O%, in 
which the term RO includes the bases KO, YO, CeO, UO, and 
CaO. —Poggendorff’s Annalen, cvii. p. 590. 
THE PSEUDO-DIASCOPE. BY F. 0. WARD. 
By means of this instrument an aperture transmitting light is 
made to produce on one eye an isolated impression, while the other 
eye is directed to an opake body, such as the hand held before it. 
The image of the aperture is then found to be transposed, and its 
perception ceases to be assigned to the eye by which it is really seen, 
—the effect being that a perforation appears in the opake body, 
through which the light seems to shine upon the eye by which this 
is viewed. ‘The principle illustrated by this instrument, according 
to the author’s view, is the essentially goniometrical and deductive 
nature of the visual act, whenever the distances of bodies are per- 
ceived, and their relative positions in space assigned.—Proc. Lit. 
and Phil. Soc. Manchester, Nov. 29, 1859. 
ON THE OCCURRENCE OF UREA IN THE ORGANS OF THE PLAGI- 
OSTOMOUS FISHES. BY G. STADELER. 
In an investigation made last year by Frerichs and Stideler, these 
observers found that the Plagiostomi are distinguished from all other 
fishes by their containing large quantities of urea in all their organs. 
The organs and the blood of Scyllium canicula, the kidneys and 
muscles of Spinax acanthias, and different organs of the Rays, con- 
