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Imk. 13 — An cnlarKCfl view oi a spt-ciincn prepared fur micrnscopic examiiiatinii. 

 The cover glass shown by the circle measures y^ inch in diameter. The mmints 

 are transverse, radial and tangential sections of a wood specimen ami wen- 

 stained to make their structure visilde under the microscope. The appearanri 

 of a transverse section of Douglas Fir at 100 di;mi'tirs !•; •.hnwti in the 

 lower illustration. 



