+---------------------------------+ | Position of | Galvanometer | | probe. | deflection. | +--------------+------------------+ | Surface ... | - 10 divisions. | | 0·2 mm. ... | - 26 " | | 0·4 " ... | - 40 " | | 0·6 " ... | - 50 " | | 0·8 " ... | - 62 " | | 1·0 " ... | - 72 " | | 1·2 " ... | - 88 " | | 1·4 " ... | -108 " | | 1·6 " ... | - 72 " | | 1·8 " ... | - 44 " | | 2·0 " ... | - 30 " | | 2·2 " ... | - 18 " | | 2·4 " ... | - 10 " | | 2·6 " ... | - 5 " | | 2·8 " ... | - 2 " | | 3·0 " ... | 0 " | | 3·2 " ... | 0 " | | 3·4 " ... | 0 " | | 3·6 mm. ... | 0 divisions. | | 3·8 " ... | 0 " | | 4·0 " ... | 0 " | | 4·2 " ... | + 2 " | | 4·4 " ... | + 4 " | | 4·6 " ... | + 5 " | | 4·8 " ... | + 11 " | | 5·0 " ... | + 22 " | | 5·2 " ... | + 38 " | | 5·4 " ... | + 46 " | | 5·6 " ... | + 39 " | | 5·8 " ... | + 32 " | | 6·0 " ... | + 24 " | | 6·2 " ... | + 18 " | | 6·4 " ... | + 12 " | | 6·6 " ... | + 6 " | | 6·8 " ... | + 3 " | +---------------------------------+ [Illustration: FIG. 177.--Curve of geo-electric excitation in different layers of _Nymphæa_. Ordinate represents geo-electric excitation; abscissa, distance from upper surface of flower stalk. The diagrammatic section underneath shows the position of geo-perceptive layer (starch-sheath) corresponding to maximum induced galvanometric negativity and positivity on the two sides.] [Illustration: FIG. 178.--The curve of geo-electric excitation in different layers of _Bryophyllum_.]