PHYSICO-TECHNICAL INSTITUTION IN CHAELOTTENBURG. 411 



mentenkunde," and the reprint for 1899 forms a pamphlet of twent}^- 

 iive large, closely- printed pages. The following abstract will convey 

 some impression, though an imperfect one, of the extent of the work 

 accomplished. 



First (Physical) Division. 



I. Work in heat. — Determination of the density of water l)etween 0° C. and 40° C. 

 Determination of the pressure of water vapor at low temperatures. 

 Determination of the pressure of water vapor near 50° C. 



Investigation of thermometers for temperatures between 100° and 200° C. 



Investigation of the nitrogen thermometer with a platinum-iridium l)ulb for \ery 

 high temperatures. 



Investigation of thermometers for low temperatures. 



Determination of the thermal and electrical conductivity of pure metals. (Tliese 

 determinations are to be extended down to the temperature of liquid air and up 

 to 1,000° C.) 



Investigations with the Fizeau-Abbe dilatometer. 



Investigation of the transmission of heat througti metal plat«s. 



II. Work in electricity. — Comparison of the normal wire resistances of Divisions I 

 and II. 



Determination of the capacity of an air condenser. 

 Comparison of the standard cells of Divisions I and II. 



Determination of the conductance of water solutions with a higher degree of accu- 

 racy than has been attained hitherto, especially with very dilute solutions. 



III. Work ill light. — Investigation with electrically heated black bodies. 

 Proof of Stefan's law between 90° and 1,700° altsolute temperature. 

 Determination of the relation l)etween the intensity of light and the temperature. 

 Measurement of radiation in al)solute measure. 



Deterniination of the distriltution of energy in the spectrum of black l)odies. 

 Determination of the distribution of energy in the spectrum of polished platiiumi 

 and other substances; also their reflective power. 



Second (Technical) Division. 



I. Work of mechanical precision. — Investigation of the errors of length and of the 

 division of 300 scales, tubes, etc. 



Coetlicient of expansion of 18 bars, tubes, and wires. 

 Verification of 86 tuning forks for international pitch. 

 Construction of a new transverse comparator. 

 Study of the variations of angular velocity of rotating bodies. 



II. Electrical H'orA'.— Calibration of direct-current appai-atus, bSo jiieces. 

 Calibration of alternating-current apparatus, 58 pieces. 

 Examination of other»electrical apparatus, 76 articles. 



Examination of accumulators, primary elements, and switches, .^7 articles. 



Examination of insulating and conducting materials and carbons, 23 articles. 



Installation of storage cells for a current of 10,000 amperes. 



Installation of small storage cells for an electric pressure of 20,000 volts. 



Installation of alternating-current instruments for measuring potential difference 

 up to 500 volts and current up to 100 amperes. 



Examination of 29 samples of alloys for specific resistance and temperature 

 coefficient. 



Examination of 126 samples of insulating materials with an electric pressure up to 

 800 volts. 



