SCIENCE— ADVERTISEMENTS 



No. 610 Model of the Atom 



Designed according to the Suggestions of 

 Professor R. R. Ramsey, Indiana University, Bloomington, Indiana 



The atom consists essentially of a coil with an iron core mounted vertically, above which 

 IS a tray with electrodes so placed that when current is sent through mercury placed within 

 the tray the current flows radially toward or away from the center. This produces a magnetic 

 held and a current at right angles and consequently there will be motion in the third direc- 

 tion and the mercury will rotate. 



The tray is connected to a storage battery. A carbon rheostat may be inserted in circuit to 

 vary the current and it is advisable to have an ammeter to measure the current. The current 

 should be from 2 to 5 amperes. 



The coil is best operated by connecting to a no volt lighting circuit with a bank of lanps 

 for resistance and the ammeter may be inserted for measuring the current. This current should 

 take from 2 to 5 amperes also. 



The amount of current necessary will depend on the adjustments and should be varied 

 so as to get the best operative conditions. 



Two balls placed on the rotating surface alternately rotate in elliptical orbits about each 

 other. 



Three balls rotate in ellipses about each other but the motion is more complicated and 

 more difficult to follow. 



A larger number of balls form a ring which rotates as a fixed, stable form. 



Various stable forms such as a ring with one or more balls in the center, or one or more 

 rings may be formed. Other phenomena such as the breaking apart of a stable form by means 

 of concentrating the lines of force through a ring outside and the illustration of radioactive 

 matter, etc., may be shown. 



A booklet of instructions describing the apparatus in detail and many atomic phenomena 

 that may be illustrated, will be sent upon request. 



Bulletins of other apparatus recently developed and illustrating some of the more recent 

 developments of science will be sent upon request. 



A SIGN or QUALITY 



A MARK OF SERVIOE 



W. M. WELCH SCIENTIFIC COMPANY 



Miuiufacturers, Importers and Exporters of 

 Scientific Apparatus and School Supplies 



1516 Orleans Street 



CHICAGO, ILL., U. S. A. 



