54 



SCIENCE-GOSSIP. 



some of the most useful pieces of apparatus : Fig. I is 

 a tripod which can be made by any working smith. 

 The legs are formed of iron rods rivetted to two rings 

 of hoop iron. My tripod is 15 inches high, and 

 34 inches across the top ring. It is used as a support 

 for the sieves during the washing process, in order to 

 leave the operator's hands free. A retort stand with 

 rings of suitable size will answer the purpose equally 

 well. 



Fig.' 2 is a tail glass cylindrical vessel, used for the 

 separation of the floating foraminifera. Such jars 

 can be obtained of any chemical apparatus dealer. 

 The spout which appears in the figure is not essential, 



generally of brass wire, copper being used for the 

 finer mesh. The most useful sizes, in my experience, 

 are 120, 80, 40, 20 and 12 meshes to the inch, and 

 the collector will do well to provide himself with as 

 large an assortment of sieves as possible, for the 

 subsequent labour of examining the material under 

 the microscope is greatly lessened, if the material has 

 first been divided into numerous grades of fineness. 

 The 120-mesh copper gauze is, I believe, the finest 

 metal gauze readily procurable, and for most materials 

 it is fine enough, as the apertures are only wsth of ^n 

 inch in diameter. With some materials, however, it 

 is necessary to use a sieve with smaller apertures. 



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fi' V 



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? '* i 



Apparatus for Preparation of Forami.mfera. 



-although a very useful feature. It is 9 inches high by 

 2+ inches diameter. The essential points in such a jar 

 are (a) perpendicular sides without neck or constric- 

 tion of any kind to prevent the foraminifera rising to 

 the surface ; {h) a foot so that it may stand un- 

 <iupported ; (c) it must be of glass, so that the 

 operator may watch the rising of the floats and 

 judge the correct time for straining them off. An 

 opaque vessel is almost useless for the purpose. 



Figs. 3 and 4 represent two kinds of sieves, which 

 can be made to order by a coppersmith. The larger 

 sieves are four inches high, four inches across the 

 top, sloping to three inches bottom diameter. They 

 • are made of sheet copper or zinc. Across the bottom 

 a piece of wire gauze is strained and soldered to the 

 outside edge so that there is no ledge of solder inside 

 the sieve to retain unwashed material. The smaller 

 sieves are made of li-inch brass telescope tubing, 

 and are one inch deep, the gauze being soldered on in 

 the manner already descriljed. 



The wire gauze may be obtained through any large 

 ironmonger, and is of varying degrees of coarseness 

 from 10 to 120 meshes to the linear inch. The price, 

 which increases with the fineness of the mesh, ranges 

 from a few pence to four shillings a square foot, the 

 smallest quantity obtainable. The coarser gauze is 



This may be effected by silver-plating a piece of the 

 120-mesh gauze so as to reduce the size of the aper- 

 tures, or preferably by using the silk gauze prepared 

 for millers, which can be bought of various grades up 

 to 240 meshes to the inch. In order to use it, the 

 collector must have a sieve made similar to fig. 3, 



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1 



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1 







z% 





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but without a bottom. The gauze is then stretched 



across and secured with a rubber band. 



Fig. 5 is a tray used for picking over material 



under the microscope. It is made by covering a 



piece of cardboard with coarse black ribbed silk. A 



piece of wood, or thick card, is then cut to the shape 



of the figure and glued on the top. When the forams 



are placed on the tray, a gentle tap scatters them 



over the surface, and the ribbed silk prevents them 



from rolling down, when placed on the inclined stage 



of the microscope. 



(To be coniinticd.) 



