SCIENCE-GOSS/P. 



579 



Every adjustment can be made from the outside, 



so that the camera need never I"' opened when in 

 work, except for changing plates All the friction 

 slides (rises, extension) arc of metal, and capable 

 of adjustment for wear. All the parts arc de- 

 tachable without removing the leather covering, 

 and interchangeable. All scales are accurately 

 measured and engraved. The front is fitted to the 

 body by a slide, which allows it to be detached for 

 cleaning, and gives the vertical rise. The bottom of 

 the front conceals the index plate, protects the 

 lever for setting the shutter and the iris diaphragm, 

 the hand and pneumatic releases, etc. 



Any lens, or several lenses, can be used. They 

 are fitted with the utmost care, and the centring 



and optical adjustments are rigorously tested. 

 The Iris diaphragm is specially constructed : it 

 cannot get out of order or wear shiny. The scale 

 of apertures is measured and engraved for each 

 lens. The shutter is of high efficiency, yet simple 

 in construction. It works between the combinations, 

 and is made entirely of metal. It is provided with 

 hermetically closed pneumatic regulation, which 

 ensures accuracy for years. It gives automatic 

 exposures from J to y^^th second and " time " 

 at will. Its action can be seen from outside. 



A self-capping device works automatically in 

 front of the lens, and protects it from dust, spray, 

 or other injuries. It also shuts off the light while 

 the shutter is being set. Focussing is effected by 

 central rackwork which acts with the utmost 

 smoothness and precision. The knob is completely 



Fig. i. N. & G-. Special B, showing Movements. 



sunk in the side of the camera. The scales are 

 divided by actual trial for each lens. Special 

 facilities are provided for tripod work. The back 

 of the camera forms a dark focussing chamber, 

 and contains a strong focussing screen the frame 

 of which is utilised for a variety of purposes. The 

 instruments are complete in every respect, and 

 provided with special tinders and T-levels for hori- 

 zontal and vertical pictures. 



( To be continued.') 



CORRESPONDENCE. 



We have pleasure in inviting any readere who desire to raise 

 discussions cm scientific subjects to address their letters to the 

 Editor at HO Strand, London, W.O. Our only restriction will 



In' in case the oonv-|Miinli'ii ■ x. •<■■-. 1 ~ tin- hounds ol 



which we trust is a matter oi great impro These 



letters may be anonymous, in thai case thej mu 

 panied by the full name and address oi the wViter, not for 

 publication, buc as an earnest of good faith. The Editor does 

 not hold himself responsible for the opinions oi the corre- 

 Bpondents, — Ed. 8.-G. 



FORAMINIFERA, 



To the Editor of SCIENCE-GOSSIP. 



Sir, — Allow me to plead for further worker- in 

 the most interesting and little-worked branch of 

 scientific research, the Foraminifera. The British 

 Isles can boast of probably not more than some 

 twenty serious students of this subject. Yet the 

 study of Foraminifera, an order of "Rhizopoda." 

 a class of the sub-kingdom "Protozoa," is so en- 

 grossing and full of interest that anyone with the 

 least taste for research, or with even a modified 

 tendency towards collecting, would only have to 

 take a cursory glance through a microscope at 

 some of these minute wonders of the marine floor 

 to be at once seized with the desire to know and 

 see more of them. 



Two volumes of the " Challenger Report " are 

 occupied by this one order of " Rhizopoda," which 

 of itself will show what a large subject it embraces. 

 One of the chief claims, in my opinion, that 

 Foraminifera have to induce a beginner to study 

 them is that one never knows at what moment 

 some species, altogether new to science, may not be 

 found in the field of the microscope. I need not 

 expatiate on the pleasure of such discoveries. 

 Again, new forms of known species are often 

 found, and, if not quite in the same category as a 

 new species, are sufficiently inspiriting to goad one 

 on to further work. 



If these minute shells are studied only with a 

 view to collecting, I can conceive no more wonder- 

 ful or beautiful collection when neatly arranged. 

 If investigated with the object of advancing the 

 world's knowledge, a tremendous scope for re- 

 search and thought is open to all. Our field of 

 operations, too, is so vast — viz. the bottom of all 

 the oceans, seas and bays of the world — that some 

 new knowledge is bound to be the result of ene 

 in their investigation. 



Another great advantage to anyone endeavour- 

 ing to decide on some way of filling leisure time 

 is that the cost of the apparatus and material 

 necessary to study Foraminifera is not great. 

 From £'12 to £15, or less, will obtain practical!] 

 all that is necessary for commencement. The 

 requirements are: a microscope, binocular for 

 choice, with inch and |-inch powers ; a condenser. 

 some microscope slides, a fine camel's-hair brush, 

 and some marine ooze, mud, or sand. Other small 

 requisites can be obtained for a mere trifle. 



The sea bottom from almost any place is gene- 

 rally found to be teeming with minute animal life 

 or their tests, otherwise shells. There are very 

 few of us without the means of obtaining a sample 

 from our own coasts, which have not yet been 

 adequately searched, as is proved by the continual 

 additions to the list of British Foraminifera. 

 Therefore, without going further, plenty of in- 

 teresting home research remains to be done by 

 . earnest workers. Fossil Foraminifera. if not so 



