SCIENCE-ADVERTISEMENTS 



rfbCUSSONS 



APPARATUS 



The " Atwood's Machine " 



The Patented Ribbon Atwood's Machine shown in the illustration 



is a new form, and furnishes an excellent means of illustrating the 



laws of falling bodies. A graphic record of the fall is made on the 



paper strip, connecting the weights. The motion of a single lever 



allows the weight to drop, and sets the pendulum in vibration. With 



the use of this machine, results are obtained which cannot be approached 



in accuracy by any other apparatus. 



Other Cussons products which have met with wide-spread approval are 

 the Mathematical Models, Capstan Block Apparatus, Machine and Steam 

 Engine Models, and Apparatus for Experimental Mechanics, catalogs of 

 which, with attractive " Duty Free" price, will be sent on request. 



JAMES G. BIDDLE: 



SOLE U. S. AGENT 

 1211-13 Arch Street PHILADELPHIA 



iWtien iQ]PhlIaaelphia be sure to visit onr Permanent Exhibit of Scientific Instruments. 



A Ne>v Invention 



The Leitz " Binocular Microscope with one objective " 



This instniment causes quite a revolution in the Microscope technique. 



The Binocular Microscope can be used with low and high powers, 

 including Oil-Immersions. 



The body contains a system of prisms whereby the binocular vision 

 with the aid of two oculars is effected. A milled head allows the 

 oculars to be placed at the proper distance to suit the interpupillarity 

 of the observer's eyes. One ocular is supplied with an adjustment for 

 the accommodation of the difference of refraction between the eyes of 

 the observer. 



FEATURES 



Restfulness to both eyes. 



Image of increased brilliancy is resolved into the minutest details. 



Apparent stereoscopic effect especially noticeable. 



The regular objectives, available in the laboratories, can be utilized. 



Price complete,;without optical equipment, duty free $79.30 



Write for literature O-70 



UNITED STATES 

 BRANCH 



NEW YORK 

 30 EAST 18th ST. 



