318 



SCIENCE 



[N. S. Vol. XXIX. No. 738 



A New Method of Measuring Association by Means 

 of Fluidity Data: Eugene C. Bingham. 



A Simplification of the Cyclical Process Method 

 for Deriving Thermodynamic Equations : E. W. 

 Washburn. 



Cuprous Hydroxide : W. D. Bancboft. 



Osmotic Studies: L. Kahlenbebq. 



Crystallization through Membranes: J. H. Wal- 

 ton. 



An Explanation of the Negative Coefficient of 

 Expansion of Silver Iodide: Gbinnell Jones. 



The Significance of certain Numerical Relations 

 in the Sugar Group: C. S. Hudson. 



The Formation of Nitric Oxide by the Action of 

 Nemst Glowers on Air: Ieving Langmuib. 



The Potential of the Sodium Electrode: G. N. 

 Lewis and C. A. Keaus. 



The Reaction Velocity of an Inorganic Hydrolysis : 



S. C. LiND. 



The Solubility of Salts in Concentrated Acids: 

 Arthuk B. Hill and John L. Simmons. 



Transition from Metallic to Electrolytic Conduc- 

 tion: C. A. Kbaus. 



A Dilution Law applicable to both Aqueous and 

 Non-aqueous Solutions: C. A. Keaus. 



Equilibrium in Solutions containing Copper and 

 Iodine: W. 0. Bbat and G. M. J. Mackay. 



The Properties of Water near the Critical Point: 

 R. 0. Mailet. 



The Internal Heat of Vaporization: J. E. Mills. 



The Molecular Masses of Liquids: G. H. MEEEa:B. 



Some Applications of the Phase Rule as a Means 

 for Determining Water in Certain Organic Sub- 

 stances : S. W. Pabe and F. W. Bliss. 



Heat Conductance of Soils: H. E. Patten. 

 B. E. Cubby, 

 New Hampshibe College Press Secretary 

 Transmitted by C. H. Herty, 



Secretary of Section. C 



SOCIETIES AND ACADEMIES 



THE TOBREY BOTANICAL CLUB 



The meeting of December 8, 1908, was lield at 

 the American Museum of Natural History, Presi- 

 dent Rusby in the chair. About seventy-five per- 

 sons were present. The announced scientific paper 

 of the evening on " Mechanical Response of 

 Plants " was then presented by Sir Jagadis Chun- 

 der Bose, professor in the Presidency College of 

 Calcutta and author of " Response in the Living 

 and Non-Living," " Plant Response as a Means 

 of Physiological Investigation," etc. The presen- 

 tation of the subject was accompanied by an 

 exhibition of some of the ingenious and delicately 



contrived apparatus constructed by Professor Bose 

 for the purpose of measuring and recording the re- 

 sponses of plants to various stimuli. Following 

 is an abstract of the paper compiled from notes 

 furnished by Professor Bose: 



The effect of stimulus impinging on a responding 

 tissue is to induce ^a fundamental molecular de- 

 rangement. This condition of derangement con- 

 stitutes excitation. On the cessation of stimulus, 

 there is a slow recovery, the tissue returning to its 

 original condition. This molecular reaction is 

 itself beyond our scrutiny, but it may be shown 

 that we can gauge its intensity and extent by the 

 observation and record of certain concomitant 

 changes induced by it in the responding tissue. 

 Among these are ( 1 ) changes of form, mani- 

 fested as mechanical response, and (2) changes of 

 electrical condition, which may be recorded as 

 electrical response. 



The intensity of the responsive change will 

 obviously depend on the two factors of strength 

 of stimulus and physiological condition of the 

 tissue. Hence, when stimulus is constant, the 

 amplitude of response gives us a measure of the 

 physiological condition. Now we know that the 

 changing environment must induce unknown 

 changes in this physiological condition, of which 

 there is no outward sign. But we are here en- 

 abled to make the plant itself reveal its condition, 

 by the reply it makes to the blow of a stimulus. 

 A stimulating agent will exalt, and a depressing 

 agent diminish or abolish, this response. We 

 have thus a means of attacking the deeper prob- 

 lem of the physiological variation in an organism. 



The speaker had been able to overcome the 

 numerous difficulties which occur in connection 

 with the automatic recording of the mechanical 

 response of the plant, by devising three types of 

 instrument. These are (1) the oscillating re- 

 corder, (2) the optical lever and (3) the balanced 

 orescograph. 



In the oscillating recorder, the recording lever 

 is made of light aluminum wire and is suspended 

 vertically on jewelled bearings. This lever is 

 L-shaped, and the shorter arm, at right angles to 

 the longer, is attached to the responding leaf. 

 The great advantage conferred by the oscillating 

 recorder lies in the fact that the friction of the 

 writing point against the recording surface is 

 practically eliminated. The source of friction in 

 such arrangements arises from permanence of this 

 contact. In this instrument, however, the writing 

 lever is virtually free, except for the brief inter- 

 vals in which the smoked glass surface is brought 

 into periodic contact with it. For these records. 



