eS THE AMERICAN MONTHLY. [March, 



BOYS' DEPARTMENT. 



Little Grains of Sand. 



By E. C. HOYT, 



DETROIT, MICH. 



Several years ago, when I conceived the idea of making a collection 

 of all the sands I could get, I undertook, from Webster's Unabridged 

 and a large line of microscopic books, particularly those upon the sub- 

 ject of mineralogy, to learn what sand really was. Although so com- 

 mon, I have never been able to find in any book anything satisfactory. 

 Definitions are quite uniform, " mineral fragments." But sands are 

 quite varied, even in the same localities. 



Along the shores of Lake Pepin there are strata of different colored 

 sands which the Indians arrange in layers in small bottles and sell to 

 passengers on the Mississippi river steamboats. 



It requires the microscope, however, to see this combination to best 

 advantage, and with the microscope and polarizer, there is a great op- 

 portunity for study at comparatively trifling expense. 



Including minei-al fragments^ by which are meant small pieces of 

 known minerals crushed into sand, I find in my cabinets over 700 va- 

 rieties, but as the subject of mineralogy is a wide one, including, as 

 Prof. Dana claims, water and ice, this article will be confined strictly 

 to sand, i. e.^ sand as found in nature, and we can refer only to a few of 

 the most striking, and touch upon some of the forms found in sand. 



Viewed microscopically, there are at least 4 classes: i. — Opaque. 

 2. — Polar. 3. — Both opaque and polar. 4. — Those which show to best 

 advantage with paraboloid. Some of the latter class are also interest- 

 ing as polar objects, although the eflect is so different that they would 

 not be recognized as the same. I have never found a sand but what 

 was of more or less interest. 



Among opaque sands are gold, silver, copper, garnet, iron, oolitic, 

 agate, diamond, pictured rocks, foraminifera, magnetic, polycistina, 

 diatom, boiling spring, and scores of other sands. 



The gold sand has little pellets of pure gold, associated with quartz. 

 The silver has fragments of wire silver ; both beautiful. The garnet is 

 a combination of angular grains of all colors. Oolitic grains resemble 

 beans, and are usually white, though one slide from Australia has 

 brown shades. The " pictured rocks " is from Lake Pepin, and the 

 larger grains are perfectly round and of a reddish shade, the smaller 

 of a variety, such as white, yellow, light green, &c., angular in shape. 

 Diamond sand is largely " Lake George" diamonds — quartz crystals — 

 very small, resembling diamonds. Others are suggested by their names. 



" Blotting sand," such as was once used, is a black iron sand. One 

 variety from Isle of Sol, Africa, resembles gunpowder, but feels like 

 asphalt. 



In many ocean sands are found things of interest, such as diatoms, 

 polycistina, foraminifera, fragments of marine animals, shells, etc. 



Polar sands are more interesting and of greater variety. Almost all 

 ocean sands are polar. The finest L have found was oft' Cape Henlopen. 



In Greenland sand each grain is a picture in itself, containing either 

 a crystal, a fluid, or an air cavity, or sometimes all. 



