A SECOND OHIO WEED MANUAL. 



2yy 



Fig. 2. Linen Tester, 

 natural size. 



A good cheap magni- 

 fier. 



will adhere firmly, being" protected by the sides of the board. In 

 such a case the holes need not be over half an inch or even less in 

 diameter. The possibilities of seed collecting- have been well 

 demonstrated in more recent years by teachers and superintend- 

 ents in their nature work in the rural schools. Some of the sets 

 of weed seeds collected by students and put up in glass vials 

 would do credit to advanced workers in this line. 



Very g-enerall}' a magnifying" glass will 

 be needed in addition to all other aids. Some 

 of these are made more expressly for such 

 work, but the grower or student will wish to 

 purchase one that will meet various needs, 

 such as the examination of parts of plants, 

 fungus spots and insects. For this purpose 

 the pocket Coddington lens, or pocket doublet 

 lens, of one-half inch focus, is perhaps the 

 best low-priced lens. It is shown in Fig. 1, 

 and costs about one dollar and fifty cents for 

 the Coddington, half-inch focus; the cost of 



the doublet lens is about one dollar. This is the most desirable 

 size to purchase for general use. 



The pocket lenses with fancy rubber and nickel frames, made 

 up of one to three glasses, are not to be compared with it in effect- 

 iveness. The best, very cheap magnifier is the "linen tester," Fig-. 

 2. It commonly sells at from thirty-five to forty cents for each lens, 

 and will usually be more effective than the rubber-cased lenses just 

 mentioned and will cost about one-half or one-third as much. The 

 linen tester is not well suited to seed work. For seed merchants 



Fig-. 3 shows a useful lens of 

 about one inch focus mounted on 

 tripod. It does not magnify 

 sufficiently for many purposes 

 but is good for rapid examina- 

 tion of a seed sample to separate 

 impurities. The seed being- 

 placed upon a paper on a level 

 table the glass is stood upon i 

 It costs about fifty cents. An 

 of these lenses may be purchased 

 through opticians or jewelers oi 

 will be sent by the makers post- 

 age paid upon receipt of cata- 

 log price. The above cuts were furnished by the Bausch & Lomb 

 Optical Co., of Rochester, N. Y., who are makers of such articles. 



Fig. 3. L- ns mounted on tripod, natural 

 size. A fjrood <rlass to examine seed for impuri- 

 ties; less desirable than the Pocket Coddinyton. 



