180 Hartmann & Braun, Bockenheim- Frankfort o. M. 



I 



means of a cloth folded upon the truck a tent can speedily be pitched 

 for the protection of the galvanometer and other instruments. A mea- 

 suring battery of 100 dry accumulators, with pachytrope for selecting 

 various voltages, and a controlling voltmeter and amperemeter complete 

 the apparatus. 



102. Portable Apparatus for measuring the resistances of 

 cable insulations, consisting of a telescopic galvanometer with 3 shunts, 

 comparison resistance, a batterj^ of 100 cells with key; in oak trunk with 

 folding feet by means of which the trunk may be converted into a stand. 

 Range up to 500 megohms. 



103. Similar Apparatus with simple needle galvanometer and 

 50 cells. Modification of the method of direct deflection, independent 

 of the voltage of the current generator. The results are found nearly 

 without calculation by a curve supplied with the apparatus. Range up 

 to 10 megohms. Weight 14 kilos. 



104. Ohmmeter, also in oak case fitted with folding legs, con- 

 taining 50 cells. Direct reading of the required resistance of the 

 insulation within the limits of 1000 and 1 000 000 ohms. Weight 14 kilos. 



105. Insulation tester for the examination of domestic installation 

 consisting of an induction coil which is made to act by continuous cur- 

 rent either upon a galvanometer of 100000 ohms resistance or by alter- 

 nating current upon a sounding apparatus with resistances up to 

 30000 ohms. 



106. Portable Bridge with direct reading for resistances of 

 solids and electrolytes, e. g. for measuring the internal resistance of 

 cells or for testing earth connections of lightning conductors. Galvano- 

 meter, easily set up. Measuring telephone and cells. All in oak case. 

 Weight 11 kilo (vid. No. 10). 



107. Portable Voltmeter and Amperemeter, mounted on tripod 

 or fitted in wood box with handle. The voltmeters intended for fitters 

 are so arranged that by means of a crank changer single portions of 

 the winding may be coupled in multiple arc or in series. The instru- 

 ments are accordingly provided with two scales, the range of one forming 

 the continuation of that of the other. The voltage may thus be mea- 

 sured within very wide limits. 



108. Simple Incandescent Lamp Photometer, constructed on 

 Foucault's principle in such a manner that the candle power of the lamps 

 may be compared without dark room. Either a paraffine candle or a 

 standard incandescent lamp may be used as a standard of comparison. 

 The ratio of intensity may be read directly by a scale with range from 

 single to 10 fold reading. The apparatus is very light being only 1 meter 

 long. It may also be used for outdoor determination of the luminosity 

 of arc lamps. 



