NOVEMBEB 15, 1895.] 



SCLENGE. 



639 



IV. On Borings through the Coral Reef in 

 Florida: A. Agassiz. 



V. On the Alkali Uranates: Wolcott 



GiBBS. 



The repoi-ts by Professors Agassiz and 

 Gibbs were presented informally in the 

 absence of other papers to occupy the ses- 

 sion. 



OCTOBER 30TH. 



VI. The Olindiadie: W. K. Beooks. 



VII. Neio Campanularian MeduscB (resid'by 

 title); W. K. Brooks. 



VIII. The Filar Anemometer: Carl Ba- 

 Rtrs. Professor Barus in this paper dis- 

 cussed the sounds by the whistling wind, 

 made whenever air in- motion passes across 

 a slender obstacle, like a wire. He 

 showed that the velocity of the wind 

 could be computed from the pitch of the 

 note observed in case of a given diameter 

 of wire and for a given temperature of 

 the air. By aid of a special microphonic 

 attachment such sound could be conveyed 

 to any distance and isolated from the at- 

 tendant noises at the place of exposure. So 

 represented, the wind was given in every 

 detail of its gusty and variable character, 

 and the term micro-aulmometry seemed to 

 be applicable to observations of this nature. 

 Finally the direction of the gust could be 

 inferred from the sounds obtained from 

 three coordinate wires at right angles to 

 each other. 



IX. The Coimtertwisted Ciirl Aneroid : 

 Carl Barus. Professor Barus reported 

 that he had investigated the maximum sen- 

 sitiveness which an extremely thin-walled 

 helical Bourdon tube would show. He 

 pointed out the importance of sharp-edged 

 tubes for the purpose of reducing the flex- 

 ure of the tube to a case of pure bending, 

 seeing that the products of the principal 

 radii of curvature must then remain con- 

 stant. He showed that for the same reason 

 the sensitiveness could be enormously in- 

 creased by untwisting the evacuated coil 



with an external spring. Furthermore, if 

 the system of countertwisting spring and 

 helical tube be so chosen that the viscosity 

 as well as the thermal coefiicients of viscosity 

 and rigidity of the components are as nearly 

 as possible the same, the system would 

 possess nearly perfect elasticity at all tem- 

 peratures. The paper was accompanied by 

 a variety of data showing the behavior of 

 simple and countertwisted helices or curls 

 and the remarkable advantages of the latter 

 form. 



X. On the Broadening of Spectral Lines by 

 Temperature and Pressure: A. A. Michkl- 

 SON. Professor Michelson's paper will be 

 printed in the forthcoming number of the 

 Astrophysical Journal and will be reported in 

 this journal. 



XI. On the Asteroids (read by title) : A. 

 Hall. 



XII. Tlie Early Segregation of Fresh-water 

 Types : Th. Gill. [Abstract will be printed 

 in this Journal.] 



THE THEBMOPHONE. 



During the recent session of the Summer 

 School of Civil Engineering of the Massa- 

 chusetts Institute of Technology, held at 

 Keeseville, IST. Y., the writer had the pleas- 

 ure of describing to the students the con- 

 struction and operation of a new instrument 

 for obtaining temperatures. This instru- 

 ment, known as a thermophone,* is an 

 electrical telethermometer of the resistance 

 type. It is designed especially for obtain- 

 ing the temperature of a distant or inacces- 

 sible place, but it embodies a principle which 

 may often be used to advantage in scientific 

 work for determining temperatures with 

 greater accuracy than can be obtained with 

 a mercurial thermometer. 



The operation of the thermophone is based 

 upon the principle that the resistance which 

 a conductor olfers to the passage of an elec- 



* Invented by Henry E. Warren and George C. 

 Whipple. 



