IIARDWICKE'S SCIENCE-GOSSIP. 



209 



of a revolving table, than the constant moving to 

 and fro, in order to set and change the objects one is 

 exhibiting. It was this untold nuisance that led me 

 to devise the apparatus as described below, which 

 will be found a great boon to microscopists not 

 possessing a revolving table. It consists of a board, 

 A, set on rollers, and carrying the microscope and 

 lamp round a house table by revolving on the 

 centre, B, through the medium of the arm on stalk, 

 C. The board, A, should be about 15 inches long, 

 9 inches wide, and \ inch thick ; the top side must be 

 covered with [thick cloth, and to the bottom side is 

 attached by screws, the stalk, C, which should be 

 of thin wood T section, to prevent vibration. The 

 stalk must be of sufficient length to obtain 

 radii varying from 18 to 24 inches to suit house 

 tables of different diameters. At | DD are shewn 



Fig. 127. — Scale, 1 inch to 1 foot. 



two pieces of wood, each 4 inches X i£- X ij thick, 

 having a shutter roller § inch diameter let in. These 

 pieces of wood must be set to radiate as shown by 

 dotted lines on sketch, and fastened to the bottom 

 of the board, A, by means of screws. As a screw put 

 into a mahogany table would be objectionable, 

 make a centre as follows : — Get a piece of wood 14 

 inches diameter, % inch thick, through the centre 

 of this pass a stout wood-screw 2 inches long, 

 then cover the bottom with thick cloth to prevent 

 it scratching the table. On to this projecting screw 

 place the stalk, C, the free end of which must be 

 bored for that purpose ; now screw on a second disc 

 of wood, 4 inches diameter, 1 inch thick, leaving 

 sufficient space between the upper and lower discs 

 for the stalk to revolve freely. Place a ten-pound 

 weight on the uppermost disc to prevent the centre 

 from slipping about the table and the apparatus is 

 complete. If the foregoing description and sketch 

 is not sufficiently clear, I shall be happy to furnish 

 further details.— C. A. Lowe, King's Hill, Wednesbury. 



Cyclosis. — The power usually employed for 

 observing this phenomenon is a quarter inch, but as 



I have been able to detect it with a two-inch objective 

 of Browning's (advertised aperture of 16 ) I make a 

 note of the fact. Selecting a good horizontally- 

 cut section of Vallisneria, I screwed an inch objective 

 into the sub-stage, fitting as a condenser, and very 

 carefully adjusted the mirror, arming my microscope 

 with a B-ocular, and only an inch objective as a 

 finder. This enabled me to ascertain the portion of 

 the section most suitable for observation. When I 

 removed the inch and replaced it with Browning's 

 two-inch, I was still able to see the chlorophyll 

 granules in motion. Of course I could only just see 

 them : the power was not suitable for any scientific 

 observation of the phenomenon. To study it com- 

 fortably and profitably a quarter inch is indispensable. 

 But while so much attention is paid to high powers 

 that beginners' hearts fail for want of them, it is 

 desirable to point out what can be done with a little 

 careful manipulation, and an effort to see into an 

 object with good low-power objectives. The 

 rotation of cell-sap can be seen with a wide angle 

 two inch ; and better still with a good working 

 one inch or half inch, although the quarter inch is 

 the glass for it.— W. J. S., Calcutta. 



Micro-Slides for Science Classes.— Mr. B. 

 Piffard has just sent out some of his slides illustrative 

 of the five orders of Coniferse. They are exquisitely 

 mounted, and comprise Taxinea (Salisburya) ; Abie- 

 tinea: (Spruce-fir) ; Araucaruc (Araucaria) ; Taxodi<z 

 (Wellingtonia) ; Cupressinea (Juniper). 



Studies in Microscopical Science, edited by 

 A. C. Cole. The second volume of this very useful 

 and highly practical work is now well on its way, 

 and, supported as we have no doubt it is, and, as it 

 undoubtedly ought to be, by numbers of new friends. 

 " The Morphology of the Cell" is continued through 

 three numbers. Amongst the slides which Messrs. 

 Cole have sent out are specimens of the Globigerina 

 ooze, Polycystina, from Springfield earth, Barbadoes, 

 and an exquisite specimen of Hebridean gneiss from 

 the Flannan island. 



Suggestions for an Exchange Club.— It 

 has occurred to the undersigned that much mutual 

 good might be effected if a small circle of really 

 ardent workers could be formed for promoting 

 the study of microscopy, amongst whom slides 

 would circulate and general ideas become common 

 property, something after the style of the postal 

 microscopical society, but with less routine, which 

 might be put briefly thus :— No fees, no secretary, 

 no journal, no annual meeting ; if at any time any 

 subject were thought sufficiently good to bring before 

 the public, the same to be done through the medium 

 of your publication. We do not desire to have a 

 large and cumbersome circle, and we do not propose 

 to dignify it with the name of club, but what we 

 desire is, a small body of really earnest workers. It 



