296 SEC. 10. ELECTRICITY. 



1490. Plate, showing Dr. Bosscha's Method of determin- 

 ing the Ratio of two electro-motive forces, with explana- 

 tory note. 



T. Bosscha, Professor, Royal Polytechnic School, Delft. 



1491. Cylindrical Condenser for measuring Capacity 



in absolute electrostatic units. Sir W. Thomson. 



1492. Adjustable Disc Condenser, also used as a spark 

 micrometer. Sir W. Thomson. 



1492a. Early Rheostat, given by Faraday to Sir Charles 

 Wheatstone. 



Wheatstone Collection of Physical Apparatus, King's 

 College, London. 



1492b. Divided Condenser, as designed by Major Malcolm, 

 R.E., for comparing the electrostatic capacities of cables, the 

 electro-motive force of batteries, &c. Elliott Brothers. 



This condenser is in 12 subdivisions, as follows, viz.: *001, -002, -002, 

 005, -01, -01, '02, -05, '1; ], '2, '5 = 1 microfarad; so that any capacity 

 from l6 1 - - to 1 microfarad can be obtained. 



1493. Rheostat with large copper wire. 



Wheatstone Collection of Physical Apparatus, King's 

 College, London. 



1494. The Original Wheatstone's Bridge. 



Wheatstone Collection of Physical Apparatus, King's 

 College. 



1494a. Rheostat (Agometer), with platinum wire. Invented 

 by M. H. Jacobi, in the year 1841. 



Physical Science Cabinet of the Imperial Academy of 

 Sciences at St. Petersburg. 



1495. Universal Resistance-Box. 



Siemens and Halske, Berlin. 



1495a. Great Lane's Measuring Flask. 



Warmbrunn, Quilitz, fy Co., Berlin. 



1496. Complete Bridge. Siemens and Halske, Berlin. 



1497. Edelmann's Small Rheochord. 



M. Th. Edelmann, Munich. 



1498. Resistance Apparatus with Weber's absolute units. 



M. Th. Edelmann, Munich. 



1499. Universal Compensator, for measuring resistances 

 and electro-motive forces. Prof* Beetz, Munich. 



The apparatus exhibited by Prof. Beetz was manufactured from his plans 

 by M. Th. Edelmann. 



