MOUNTS OF WOODS FOR STEREOPTICON. 



These are transverse sections from 1-400 to 1-600 in. thick, mounted 

 between glass of standard steropticon-slide size, 3^ x 4 in., and enable the 

 display of characteristic wood-structures, projected from nature itself, in a 

 most satisfactory manner. The wood-section covers a circular field gen- 

 erally 2^4 in. in diameter on the slide. It is surprising, to one who has not 

 seen, how much of interest there is in these large and very thin transverse 

 sections of the woods. With them the annual rings (indicating age and rapidity 

 of growth) or their absence, the medullary rays, the arrangement of ducts, 

 the cells of the wood, etc., can be shown on the screen with striking vividness 

 projected from nature itself. One can scarcely forget the first impression of 

 such a display. They are invaluable for the lecture room. For illustrating talks 

 on particular trees with lantern these mounts and our views of trees, etc. (See 

 p. 15) together furnish ideal and very complete material. 



But it is not for the lantern alone that these mounts of woods are in- 

 valuable. As hand specimens, to examine with unaided eye or with simple 

 magnifier, they are equally useful and interesting. Many a revelation is 

 found in them, and one is the fact that the transverse sections of the woods 

 of all of the cone-bearing trees (Coniferae), when looked through towards 

 a bright light while the observer is in the darkness, show a brilliant display 

 of the colors of the rainbow the " fine grating spectrum," Very few other 

 woods show them, and those but dimly. 



Price 50 cts. each. 20% discount on quantities of 25 or more 



The actual size of these slides 

 is 3 ]/4 x 4 in., the standard size 

 of lantern slide commonly em- 

 ployed in this country. We can, 

 however, make up the mounts in 

 any size or shape of slide desired, 

 and at the same prices. 



STEREOPTICON MOUNT 

 OF WHITE OAK WOOD, REDUCED 



