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Mr. J. Small. Changes of Electrical 



and quickly withdrawn, uo injurious effects were observed. Tliis was tested- 

 by removing the wax tip and growing the beans for about 10 days afterwards.. 

 The wires were inserted on the same side of the root, the first 1 mm. from 

 the apex and the second 2 mm. from the apex. This operation requires 

 much practice and a considerable amount of patience if the root is not to be 

 injured to such a degree that the succeeding stages are useless. The wax 

 covering serves the double purpose of keeping the root from drying and of 

 insulating the wires from the surface of the root. A root-tip covered 

 with wax in this way will remain fresh for hours after the unwaxed 

 portion is strongly withered, and the aerating system of the root of 

 Vicia Faha is efficient enongh to provide the necessary opportunities for 

 respiration in the covered portion of the root (4). The wires were fixed in 

 position by a plug of wax melted around them, so that a longitudinal section 

 of the root-tip, fitted witli wires, would show something like fig. 4. The- 



placing of the plant at any desired angle was accomplished by means of the- 

 apparatus figured (fig. 5). 



The supports C and E were clamped to a shelf, AB, A wooden support, D,. 

 with a socket in it, was supported by C. The angle was indicated upon a 

 scale, 0, marked upon a smooth piece of mahogany with a socket at the 

 centre of the semicircle. The scale was divided into 36 angles of 5° each,, 

 and holes were made in the proper places so that a plug, P, could be inserted 

 to support the swinging portion of the apparatus at any required angle. 

 The orientation of this scale was checked by means of a plumb line T. Eor 

 convenience in fixing the plant a piece of sheet cork, H, was screwed to a 

 wooden base, G. This base had 'a vertical line drawn along the centre of the 

 length and another line at right angles to it, at about one-third of the length, 

 from the top. At the ends of the latter line steel rods, G', G', were inserted 

 to give an axis upon which the part swung when the free ends were inserted 

 in the sockets of D and 0. The sheet cork was thoroughly waxed, and a 

 thread, S, was fixed along it coinciding with the vertical line on the wooden 

 base. The orientation was checked with a set square, a plumb line, K, and 



ROOT 



WAX COATING 



Fig. 4. 



