1895.] 



481 



one-tenth of an inch — will give a rise of one one-hundredth of 

 an inch to the compound body. The free extremity or long 

 arm of the lever is raised by a rod fastened to the cradle fur- 

 nished with a screw ten threads to one inch so that one- tenth 

 of its revolution in such a case would mean a change of one 

 one-thousandth of an inch in elevation or depression of the 

 compound body. In this way a fine adjustment is provided, 

 which is also capable of measuring accurately the penetrating 

 power or depth of focus of any lens or objective placed on the 

 compound body. The stage is formed of a glass slide or plate 

 of glass held firmly to two prongs of brass projecting from the 

 lower end of the cradle by two brass clips or springs — thus 

 admitting of free motion by the fingers of the observer in any 

 direction, and of firm retention of the slide in any position, 

 yet without any appreciable depth of staging ; to the under 

 portion of these prongs, however, any substage accessories 

 may be attached, such as prisms, condensers, etc. The mirror 

 is jointed to the cradle so that light can be thrown on an ob- 

 ject at any angle. And if it be desired to measure the work- 

 ing angle of aperture of any objective it may readily be done 

 by a scale placed concentrically with the object examined. 

 The cradle rests on the pillar movably so that it may render 

 the compound body useful at any angle between 80° and 15°. 



" The materials for this microscope cost us $12.67, including 

 $10 paid for a one-eighth objective regarded as useless by 

 the optician from whom it was purchased on account of wrong 

 spacing between outer and middle lens, which was remedied 

 by slipping the collar : the putting it together occupied us two 

 days. It proved very useful as a field instrument which if 

 broken could readily be repaired." 



Prof. E. D. Cope read by title and explained the contents of 

 two communications, " The Reptilian Order Cotylosauria " 

 and " On Some Plistocene Mammalia from Petite Anse, La." 



Dr. D. G. Brinton read a paper entitled " Some Words from 

 the Angagueda Dialect of the Chocos," and illustrated by a 

 map the positions of the various tribes in Northern South 

 America and their linguistic relations to each other. 



