Intelligence and Miscellaneous Articles. 291 



magnitude occurring in the bulb of a thermometer would mean a 

 displacement of the zero-point by -^°. 



ON A TELETHEEMOMETEE. BY PEOF. DR. J. PULUJ. 



The author gave the following abstract of a long paper on this 

 subject : — 



The present paper contains the description and theory of an 

 apparatus, which renders it possible to transfer to a distance the 

 indications of any given temperatures. The construction of the tele- 

 thermometer depends on the use of two conductors, the resistance of 

 which varies with the temperature in opposite directions, and which 

 -form the thermometric part of the apparatus. The latter consists 

 of a small glass tube closed at both ends, which contains a carbonized 

 strip and a spiral of platinum wire, and which is filled with 

 hydrogen in order to conduct the better. The carbon strip and 

 the iron spiral form two branches of a Wheatstone's bridge, and 

 by means of three wires are connected with a measuring-scale which 

 has an empirical scale of temperature in Centigrade degrees. The 

 resistance of the carbon strip decreases with the temperature, while 

 that of the iron increases, and in accordance with this the zero of 

 the difference of potential is altered. The temperature may be 

 determined either by means of an astatic galvanometer, or by a 

 telephone with a microphonic contact-breaker in such a manner 

 that contact with the measuring-wire is deferred until the galvano- 

 meter shows no deflexion, or the telephone gives no sound. The 

 telethermometer renders it possible to determine temperatures at 

 a distance of 1 km. to within o, l C. 



In the theoretical part of the paper the displacement of the 

 contact along the wire is calculated, and the graduation of the 

 telethermometer is completely discussed ; this is followed by a 

 calculation of the correction of the scale for temperature, and the 

 proof is given that a rise of temperature of the wire bridge has no 

 influence on the indications of the telethermometer. It is shown in 

 conclusion how the telethermometer may be used as an indicator 

 of temperature, which automatically gives the temperature at any 

 instant.— Wiener Berichte, Oct. 10, 1889. 



ON THE MEASUREMENT OP ELECTEOMOTIVE CONTACT FOECES OF 

 METALS IN DIFFEEENT GASES, BY MEANS OF THE ULTBA- 

 VIOLET EAYS. BY A. EIGHI. 



Since, as is shown by the earlier experiments of the author, ultra- 

 violet rays bring to the same potential bodies which are very close 

 to one another, the differences of potential of contact can by this 



