152 THE MICROSCOPE. 



Stipate Diatoms may be found adhering to the larger alga? 

 and similar water plants, tinted with a reddish brown. 



When collecting, a number of phials with wide mouths, furn- 

 ished with corks, should be carried. The mouth of the bottle 

 being closed with the thumb it is brought close over the cov- 

 eted colony in the water, and on removing the thumb, the 

 water and Diatoms will rush in. A spoon is frequently used 

 in removing layers of Diatoms from sand at the bottom of pools 

 and rivers. If the masses of Diatoms are entangled amongst 

 algae, they may be detached and collected by means of muslin 

 nets affixed to a rod. Telescopic rods, like Japanese fishing-rods 

 can be procured for carrying the net or a bottle, and are often 

 useful in obtaining specimens which would be otherwise be- 

 yond reach. 



Diatomacese are, as has already been stated, found in fossil 

 form in great numbers, seldom however containing a great va- 

 riety of species. The mass may sometimes be disintegrated by 

 placing lumps of it in a test-tube, covering them with Liquor 

 potassse, boiling for a short time until the whole breaks up into 

 a sort of mud, which should instantly be poured into a quan- 

 tity of distilled water and well washed. 



THE INVENTOR OF THE FIRST PAPER BAG MACHINE. 

 By R. G. DUBOIS, WASHINGTON, D. C. 

 [feom the inventive age.] 



The man who produces a useful invention does more for hu- 

 manity than the discoverer of a planet. The Rev. Francis 

 Wolle was the first man in the world to invent and build a ma- 

 chine for making paper bags. Before his day, paper bags were 

 made by hand and were too costly for ordinary use, being held 

 in reserve for the more expensive class of goods, but after his 

 invention they became more commonly used than ordinary 

 sheets of paper. If we should aggregate the time saved to each 

 waiting customer in a store, by the use of bags instead of the 

 old sheet folding process, it would amount to enough to build 

 forty railroads around the globe. Dr. Wolle was born in 1817, 

 and when about sixteen years of age was employed in his fath- 

 er's store at Bethlehem, Pa. While engaged there the idea of 

 making paper bags by machinery first entered his thoughts, but 



