624 



SCIENCE. 



[N. S, Vol. ]X. No. 226. 



surface is' decayed as if no removal or grind- 

 ing of the surface material had taken 

 place by glacial action, and is entirely free 

 from drift boulders. As a probable explana- 

 tion the author suggested that this area lay to 

 leeward of a great ice ridge which eflfectually 

 shielded it from the direct action of the glacial 

 ice stream. 



Mr. H. B. Humphrey detailed his observa- 

 tions upon the influence of low temperatures 

 upon plants, and described the difference of 

 effect of sudden changes and gradual lower- 

 ing of the temperature. Living specimens kept 

 for a month or more in commercial cold-storage 

 rooms at a point slightly below freezing ex- 

 hibited phenomena of starvation. 



Charles P. Berkey, 

 Corresponding Secretary. 



Minneapolis, Minn. 



the academy of science of st. louis. 



At the meeting of the Academy of Science of 

 St. Louis of April 3d a paper by Mr. Stuart 

 Weller, entitled ' Kinderhook Faunal Studies, 

 I: The Fauna of the Vermicular Sandstone at 

 North view, Webster county, Mo.,' was pre- 

 sented for publication ; and Mr. Trelease ex. 

 hibited a plaster cast of a gigantic monstrosity 

 of Cereua marginatus, known as the Rosa de 

 Organo, presented to the Missouri Botanical 

 Garden by Professor Frederick Starr, and re- 

 ported that this formation was locally abun- 

 dant at points south from Aguas Calientes. The 

 speaker exhibited a large number of compa- 

 rable cactus monstrosities from the plant-houses 

 of the Missouri Botanical Garden and the col- 

 lection of the President of the Cactus Associa- 

 tion of St. Louis, and a similar deformity of one 

 of the cactus-like Euphorbias of the African re- 

 gion, commenting on this teratological type. 

 It was shown that for the purposes of gardeners 

 for whom these unusual forms appear to pos- 

 sess a considerable interest, they are commonly 

 divided into two types, in one of which, com- 

 monly designated by the varietal name cristata 

 or cristatus, the monstrosity takes the form of 

 a fan or a contorted ridge, while in the other, 

 commonly designated by the varietal name 

 monstrosa or monstrosus, it consists of irreg- 

 ular bunching of the branches and an interrup- 



tion of the customary longitudinal ridges of 

 such a genus as Cereiis. 



William Trelease, 

 Recording Secretary. 



boston society of natural history. 



A GENERAL meeting was held March 15th ; 

 twenty-eight persons present. 



Mr. E. C. Jeifrey, in an account of the genus 

 Eqiiisetiim, stated briefly the sexual and asex- 

 ual methods of development. The internal 

 structure of the stem was described, and the re- 

 lationships of the EquisetjB to the Lycopods 

 and ferns were noted. Structurally Archffio- 

 calamites resembles the higher Lycopods. The 

 branches of Calamites originate from the center 

 of the ring of nodal wood or from its lower 

 border. Casts of Calamites show pith. 



Dr. C. R. Eastman read a paper on some new 

 North American fossil fishes. An abstract will 

 appear in an early number of Science. 



Samuel Henshaw, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 



ON THE action op THE COHERER. 



Experiments have been made at the physical 

 laboratory of the Missouri State University 

 which show that the action of the Branly tube 

 is due to an actual cohering of the particles. 

 The action consists, first, in an electrostatic at- 

 traction causing the particles to come in con- 

 tact, and] second, in a fusion of the points of 

 contact. 



An instrument has been designed and con- 

 structed which clearly shows this coherence 

 and renders its study possible. It consists of 

 two electrodes, one a metallic plate on which 

 the filings are placed, and the other a metallic 

 point carried on a pivoted arm swinging in a 

 vertical plane. If a considerable difference of 

 potential is maintained between these elec- 

 trodes, and the point be brought in contact 

 with the filings and then carefully lifted, a 

 thread will attach itself to the point and may 

 be drawn out to two or more inches in length. 

 The difference of potential has, in our experi- 

 ments, been produced in a variety of ways. 

 Thus the instrument was placed in circuit with 

 two dry cells and a 160-ohm relay, and threads 



