Journal of Applied Microscopy. 621 



Forms observed : / (111), e (101), /i (133), j (3.11.11), k (155), / (1. 11.11) ; 

 with the two latter faces tending to form a curved surface. Pyramidal hemi- 

 hedrism strongly emphasized, and measurements confirm axial ratio of Melville 

 and establish isomorphism of the species with scheelite group. Author mentions 

 probability of some darker blue, more massive powellite proving to be pure 

 calcium molybdate, thus constituting the missing end of the scheelite-powellite 

 series. ~ L. mci. l. 



Senaite. A new Mineral belonging to lime- Black in color, with sub-metallic lustre, 

 nite Group from Brazil. E. Hussak and o^. i u • u ui„„i xt^^ ,^^^ 



G.T. Prion Min. Mag., 12: 30,1898. Streak, brownish-black. Non-mag- 



netic. Transparent in thin splinters. 

 Composition = Ti O,, 57.21; PbO, 10.51; FeO, 4.14; FeA, 20.22; MnO, 

 7.00 ; MgO, 0.49 ; SnOj, 0.11 = 99.6». Two analyses recorded, but leading 

 to no satisfactory formula. Approximately (Fe Pb) 0.2 (Ti Mn) Oj. Rhombo- 

 hedral (trigonal rhombohedral of Groth) with f = 0.997. Rich in faces, and 

 " supplementary " twins very common. Rombohedral planes bright, while basal 

 planes (due to twinning) and prism faces dull. Weakly doubly refracting, non- 

 pleochroic and uniaxial. No cleavage and conchoidal fracture. H. = 6 -f-. 

 G. = 4.22 to 5.301. Infusible before blowpipe. Decomposed by boiling sul- 

 phuric acid. Found in rounded fragments and rough crystals (which may be 

 partially decomposed) in diamond-bearing sands of Diamantina Minas Geraes. 



L. McI. L. 



Sphaerostilbite. G. T. Prior. Min. Mag., 12: Improbable that the mineral exists 

 26, 1898. ... 



which was described under this name 



as a sub-species by Beudant. Heddle's sphaerostilbite probably consists of 



thomsonite in sheaf-like aggregates implanted upon more compact thomsonite. 



The name should be discarded as a structural term apphed to stilbite. 



L. McI. L. 



NEWS AND NOTES. 



Answer to Correspondent. — The cover-glasses that could not be cleaned 

 after treatment with HNaCOg were probably chemically acted upon by the 

 solution. Alkalies have an etching effect upon glass, especially when hot 

 solutions are used. 



Apparatus for Removing Bubbles from Mounts. — In the course of my 

 peregrinations among the laboratories of the North of England, I have, upon 

 several occasions, met with a small exhaust apparatus which is used for the 

 removal of air bubbles from mounts. It is simple in construction, and effective 

 in action, and a description of it may not, therefore, be without some interest to 

 readers of the Journal of Applied Microscopy. It consists of a slip of 

 plate glass measuring 4" x 1}4", to which a frame of wood has been cemented. 

 The frame is of such a size as to allow of ordinary glass micro-slips being 

 placed in it. 



In one side of the frame a hole is bored, and one end of a piece of India- 



