6 THE AMERICAN BOTANIST. 



you feel the need of a higher power objective before you buy 

 one. By that time your acquired skill will enable you to use 

 it safely and efficietly. 



For more advanced work in plant histology a good 1-6 

 or 1-5 is needed and a double nose-piece to carry it and its 

 low power mate. A "divisible objective" is one in which the 

 front combination may be unscrewed, permitting the use of the 

 back combination as a low power. Optically it does the work 

 but practically its use is very tiresome. There is an ever re- 

 curring danger of dropping or scratching the front lens while 

 making the change. Be content with a good low power alone 

 until you can afford a 1-6 and a nose-piece to effect the 

 changes. 



Now as to a 'stand' as the supporting parts of the instru- 

 ment, are collectively termed. A joint for inclination adds to 

 the cost and is not an essential feature in botanical work. Plant 

 tissues are usually examined in water or other liquid and con- 

 sequently with a horizontal stage. In long continued examina- 

 tion of mounted specimens the inclined position of the tube is 

 easier on the neck muscles of the examiner. Photo-micro- 

 graphy and the projection of images of mounted objects upon 

 a screen also require a horizontal tube and consequently a 

 joint for inclination. 



If the mind's eye is looking ahead to original research 

 into bacterology, diatomaceae, karyokinesis and other delight- 

 ful polysyllabic possibilities it would be well to look out in 

 advance for facilities for attaching a sub-stage condenser. 



The writer once knew a boy who had the temerity to 

 make a compound microscope. The result may have been 

 lacking in mechanical precision but it afforded its owner a 

 great amount of rational amusement. We are not advising a 

 general following of such a plan but an ingenius amateur, 

 handy with tools will really find little difficulty in making a 

 temporary stand to support an eye-piece and objective in 



