MOVING PHOTOMICROGRAPHY— KAZEEFF 325 



By a slight modification of the G, V., a period of pose is obtained 

 which is five times longer than the period of juggHng or closing, and 

 this is for a speed which can exceed 32 images per second (the normal 

 speed being 16 images per second). Tliis result is attained by means 

 of a cog that raises the catches and prevents their taldng up the 

 perforations of the film for a duration that would correspond to tliree 

 images if these catches were free to work. At the moment which 

 would correspond to the end of the pose of the fourth image, the 

 catches are lowered and drawn along the film the length of an image, 

 at a speed three times greater than that of a normal apparatus for 

 the same time. The time of pose is thus twice as long as in the regu- 

 lar apparatus. This is an important unprovement in the photo- 

 graphic utilization of time and light flux. It permits maldng moving 

 pictures of delicate subjects that are sensitive to the light, by utiUzing 

 a weak light source while keeping the rapid time that is necessitated 

 by the speed of their movements. 



An accessory arrangement provides for a record of the time on each 

 image, which shows the exact speed of the photograph taken. This 

 record is obtamed with the aid of a very small objective placed on 

 the left side of the apparatus which by means of a prism in a circle 

 of 3 millimeters diameter situated in an upper comer of the film, 

 gives the image of a chronometer with a transparent dial g, placed at 

 a determined distance in front of the objective and lighted by a little 

 incandescent lamp h. Each image records thus the minute and even 

 the fraction of second of the pose. By substituting a thermometer 

 or galvanometer needle in the chronometer, there can also be regis- 

 tered the temperature, the direction of an electric current, or any of 

 the other conditions of the experiment. 



The moving-picture apparatus fixed sohdly on a slide can be raised 

 or lowered along the cast-iron arm with a minimum of effort by 

 means of a regulating wheel i. When it is raised to the maximum, 

 the experimenter can look into the microscope and observe the prep- 

 aration directly. At the moment of photographing, the apparatus 

 is placed at the desired distance for a determined enlargement indi- 

 cated by an index which slides on a metric rule j fastened to the iron 

 structure. The junction of the light between the microscope and the 

 film is obtained by means of a bellows with an extensible draft. 



An important improvement apphed by Dr. Comandon is a tele- 

 scope system k and a prism that not only makes possible direct focus 

 upon the film but also continuous observation of this while photo- 

 graphing. The moving objects can in this manner be maintained in 

 the field by adjustment of the microscope screw and observation can 

 be continued without interruption of the microscopic preparation re- 

 flected on the unexposed film, in the same manner that a photograph 



