SCIENCE-ADVERTISEMENTS 



Earth Inductor ^nd Dynamo 

 Analysis Apparatus 



No. 1S9S 



No. 2410 



1898 — EARTH INDUCTOR, New Design. The coil contains 1,000 turns of wire of 

 about 250 ohms resistance and is wound on a mahogany finished ring 22 cm. in diameter. 

 It is mounted so that pressing the release button causes the coil to quickly turn 180 de- 

 grees automatically by means of a strong spring. It is arrested at 180 degrees. This 

 automatic arrangement avoids the errors previousl3'' encountered due to not turning the 

 coil at uniform speed in separate determinations. This coil is mounted so that it may 

 be used in either a vertical or horizontal position and cut either component of the earth's 

 field. All metal parts of brass or non-magnetic. Handsomely finished and very durably 

 made. V/ith instruction sheets. 



2410 — DYNAMO ANALYSIS APPARATUS. For showing the wave form of the 

 induced current when a coil rotates in the magnetic field. This instrument embodies 

 the ideal dynamo for showing induced current in the generator at any part of its revolu- 

 tion. It consists of very powerful horseshoe magnets mounted so as to produce an intense 

 and yet a uniform magnetic field within the space in w^hich the coil is made to turn. By 

 means of the graduated arc the amount of current through a galvanometer can be 

 measured for each ten degrees of turning of the coil. This w^ill show the gradual increase 

 of the generator electromotive force and its rise to a maximum and its decrease to zero 

 and the reversal in the other direction as a coil rotates. Very durably made, and hand- 

 somely finished, and a complete instrument for demonstrating this important principle. 

 Designed especially according to specifications of Millikan &: Mills "Electricity, Sound and 

 Light," Exp. 12. Length over all about 30 cin. With instruction sheets outlining de- 

 tails of experiment. 



COMPLETE CATALOG OF PHYSICS AND CHEMISTRY APPARATUS 

 CATALOG "G" 



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