922 



SCIENCE. 



[N. S. Vol. XX. Xo. ry2 



edly derived from sea water and are not as- 

 sociated with nitrogen. 



The last paper was presented by Dr. Aller- 

 ton S. Oushman, who discussed the ' Action 

 of Water on Eock Powders,' in the light of 

 investigations which have been carried on 

 in the division of tests of the U. S. Depart- 

 ment of Agriculture. It has been found that 

 wet grinding increases the binding power. 

 This effect seems to be accompanied with 

 direct decomposition of certain constituents 

 of the rock magma which results in forming 

 colloidal films on the particles. The word 

 ' pectoid ' is suggested to describe this condi- 

 tion. Most rock powders that have been 

 ground wet show an alkaline reaction .to indi- 

 cators, but if the water is filtered out the 

 reaction is not usually shown. The analogy 

 between the reactions that take place when 

 Portland cement, powdered glass and rock 

 powders are acted on by water was pointed 

 out. The paper was illustrated with the lan- 

 tern. Microscopic slides were shown with 

 polarized light and indicated that the pectoid 

 films could actually be seen on the surfaces 

 of the wet ground particles. 



A. Seidell, 

 Secretary. 



THE PHILOSOPHICAL SOCIETY OF WASHINGTON. 



The five hundred and ninety-first regular 

 meeting was held November 26, 1904. 



The first paper was by Mr. Edgar Bucking- 

 ham of the department of agriculture on ' The 

 Aeration of Soils,' describing recent experi- 

 ments on various kinds of soils to find the 

 rates of diffusion and transpiration through 

 them, and the density and composition of the 

 gas normally in the soil. Among other things 

 it is found that the proportion of 00^ in- 

 creases downwards while the oxygen decreases, 

 the nitrogen remaining nearly constant at 79 

 per cent. 



Mr. W. P. White, of the geophysical labo- 

 ratory, then spoke (by invitation) on ' Meth- 

 ods of Measuring the Intensity and Damping 

 of Hertzian Waves.' 



A null method was used, which eliminated 

 the effect of variations in the spark to such an 

 extent that determinations could be made to 



agree within one fifth per cent. Fine plat- 

 inum wire bolometers in vacuo were used, 

 which are more sensitive than thermocouples. 

 When the wire is very fine the resistance and 

 sensitiveness are such as to make aperiodic 

 receivers practicable. The problem of getting 

 interference curves in free air seem thus to 

 be solved. This also renders possible a new 

 method of measuring damping, in which one 

 of two interfering wave trains has its intensity 

 varied by a polarizing mirror. Practically 

 exact interference between the overlapping 

 portions of the two trains is thus secured, and 

 by varying the length of the unquenched por- 

 tion the intensity of the separate oscillations 

 can be measured, one by one. Like all in- 

 terference work with damped trains, this 

 method requires pure waves. 



Both papers led to considerable discussion. 

 Charles K. Wead, 



Secretary. 



THE TOREEY BOTANICAL CLUB. 



The meeting was called to order at the usual 

 hour November 30, at the New York Botanical 

 Garden, Professor L. M. Underwood in the 

 chaii', twenty members being present. The 

 following were elected to membership : Miss 

 Mabel Denton, of Paterson, N. J.; C. B. 

 Eobinson, of New York, and Dr. G. H. Shull, 

 of Cold Spring Harbor, N. Y. 



The first paper on the scientific program 

 was entitled ' Recent Contributions to our 

 Knowledge of Paleozoic Seed Plants,' and was 

 by Edward W. Berry. It consisted of a brief 

 discussion of recent contributions to our 

 knowledge of those Paleozoic pteridophytes 

 which had formed, or approximated, the seed 

 habit, the work of Professors Scott, Oliver, 

 Kidston, Grand, Eury, Zeiller and Renault. 

 Especial attention was given to the work of 

 Scott and Oliver and to what amounted to a 

 demonstration by them of seed bearing in the 

 cycadofilicean genus Lyginodendron (Sphen- 

 opteris). 



C. B. Robinson presented ' Remarks on the 

 Flora of Northern Cape Breton.' To the 

 north of the Bras d'Or Lakes the island of 

 Cape Breton consists of hills 800 to 1,500 feet 

 in height, bordered by lowland of no great 



