128 THE AMERICAN MONTHLY [June, 



Some Trifles Worth Knowing. 



By E. H. GRIFFITH, 



FAIEPORT, N. Y. 



Lateral Motion. — Many who are versed in optics forget certain 

 well-known laws of light when they are using the microscope, and the 

 result is sometimes expensive. Only a few days ago, while visiting a 

 microscopist, he told me of an exchange of stands that had been made 

 by a physician of the city with the representative of a microscope man- 

 ufactory. The agent by pushing the mirror one side convinced the 

 doctor that his instrument tube had lateral motion, then by setting the 

 mirror of his own instrument central its superiority was easily demon- 

 strated to the amateur, and he paid a good sum in exchange. If those 

 who own microscopes will devote a few hours to the diflerent results 

 obtained by changing the position of the mirror they will be well paid 

 for their time and trouble. Oblique illumination will give the appear- 

 ance of lateral motion in the tube of the best microscope ever made. 



High Powers in Oculars. — Not long ago, while experimenting 

 with my microscope, I removed the field lens of the eye-piece and laid 

 it on top of the eye-lens. To me the result was a surprise. Let those 

 who desire extra power in oculars try the experiment. 



A Cheap Condenser. — One day, when in St. Paul, Minn., a friend 

 showed me some glass globes which were filled with liquid and which 

 were being sold for microscopes of wonderful power. My friend being 

 an enthusiastic microscopist, condemned the toys. I suggested that he 

 fit the end of the stem of the globe to a bit of wood which could slide 

 in the groove of the mirror-bar and above the mirror and that he use it 

 as a condenser. A few hours later I called to see him, and I found him 

 at work with his 25-cent condenser, which gave very satisfactory results. 



Microscopical Laboratory Notes.* 



By H. M. WHELPLEY, Ph. G., F. R. M. S., 



ST. LOUIS, MO. 



Dissecting Knives. — The delicate blades of small dissecting knives 

 are liable to become injured if the instruments are not carefully cared 

 for when not in use. I find that a small piece of thick blotting-paper 

 can be slipped over the blade like a sheath to a sword. If the blade is 

 dipped in vaseline before putting it away there is no danger from rust. 



A Clean Cloth. — It is customary to have an old silk handkerchief 

 convenient for the purpose of wiping ofl^ objectives, cover-glasses, 

 slides, etc. It is also quite common to see this cloth left out in the dust 

 and dirt. I keep the piece of old silk in a tight box, so that it is not 

 gathering dust when not in use. When it becomes soiled it should be 

 washed. 



Labeling Slides. — Not every one stops to think how much more 

 convenient it is to have the principal label on the left hand end of a 

 slide. We naturally pick up a slide with our right hand and grasp it 

 by the right hand end. This covers up the label on that end, so I 

 make it a practice to place the label on the left hand end ; or, if two 

 labels are to be used, I put the main one on this end and the less im- 

 portant one on the I'ight. 



* Read before the St. Louis Club of Microscopists. 



