Popular Science Month! j/ 



301 



placed in the center of the ring. The object 

 of the threads is to prevent the drop of 

 water running around the sides of the cell. 



A reservoir slide, Fig. 2, is sometimes con- 

 venient, particularly for the examination of 

 algae, as it provides a relatively large volume 

 of nutritive fluid. A useful trough can be 

 made on a 3 by llo-m. slip in the following 

 manner: Cut a piece of fiat and parallel- 

 sided hard rubber to the shape shown at.Z>, 

 so as to make a trough about 1 M by ^ by 3-4- 

 in., and cement this to the slip midway 

 between the ends and flush with the sides. 

 Cover this with an oblong cover glass or a 

 piece cut from an object slide, cemented on 

 water tight. Two small pieces of glass, E 

 and F, should be cemented to the slip to 

 form ledges on which a circular cover glass, 

 Gy can rest without risk of its slipping down 

 into the trough. A filament of growing 

 algae, H, is shown ready for examination, 

 having been passed up from the trough in 

 which it was growing, and covered with the 

 thin cover glass. 



In Fig. 3 is shown another useful though 

 very simple device. It consists merely of a 

 3 by 1-in. slip, around which two pieces of 

 silk or cotton threads, / and J, are tied a 

 short distance apart, the covered glass, K, 

 being laid across them. This forms a 

 shallow cell which is open to the air almost 

 all around. The water can be renewed as it 

 evaporates by adding a drop to the edge 



F1G.3 

 A slide that provides a way to renew 

 the water by adding a drop to the edge 



without disturbing either the object or the 

 glass. The drop will be sucked up by capil- 

 lary attraction. Areation of the water is thus 

 facilitated. 



In order to make the slide rest firmly on 

 the stage, stick small pieces of paper, L and 

 M, to the underside, one at each end. Several 

 slips may be prepared, using different thick- 

 nesses of thread. These may be numbered 

 in accordance with the depth of the cell. 

 The numbers should be written on one of 

 the paper strips so that they may be read 

 through the glass. — H. J. Gray. 



Cane Chair Seats and How to 

 Weave Them 



THERE are seven steps in the weaving of 

 the cane for a chair bottom, or other 

 paneled work. These are described and il- 

 lustrated in a new book, entitled Seat Weav- 

 ing, by L. Day Perry (Manual Arts Press). 

 First of all, the cane must be soaked for a few 



%' 



t 



v;. 



0990 



Layout for holes to be 

 bored in the seat frame 

 for holding the cane 



miinutes in warm water. Cold 

 water will do, but it takes 

 longer to make the cane 

 pliable. Be careful not to 

 soak the cane too long. In- 

 sert one end through a hole, 

 next to a corner hole, allow- 

 ing it to project about 3 in. below, and fasten 

 it by driving a peg in the remaining part of 

 the hole. Pull the entire strand through be- 

 tween the thumb and forefinger to prevent 

 its twisting, and run the other end down 

 through the opposite hole, next to the corner 

 hole. Make sure that the smooth side of the 

 cane is out on the underside of the frame as 

 well as on top. In doing this, the cane is 

 pulled reasonably taut, then fastened in the 

 latter hole with a peg to prevent its slipping 

 back and becoming loose. Draw the cane 

 through between the thumb and forefinger 

 again, pull it over to the next hole, or second 

 one from the corner, and run the end up 

 through and across the top, parallel to the 

 first strand, and down through the opposite 

 hole in the other piece, or second hole from 

 the corner, and fasten with a peg. This 

 operation is repeated until all holes have 

 been utilized on the two parallel rails, except 

 those at the corners. Throughout the seven 

 operations, the cane must be kept from twist- 

 ing by drawing it between the thumb and 

 forefinger. With this first step completed, 

 all holes in the two rails opposite will be 

 entered, with all cane running parallel and 

 on the upper side, the cane crossing from 

 hole to hole on the underside. 



The second step is just the same as the 

 first; the only difference is that the other 

 two rails of the frame are used and that the 



