18 DIATOMAORS, 



isms causing the luminosity of the ocean, yield rich crops of 

 diatoms, and should be secured. Such gatherings may be put 

 up as obtained, or have alcohol added to them for better pre- 

 servation. The collection of aquatic plants from the mouths of 

 rivers is extremely desirable, — such as have been made in the 

 delta of the Ganges yielding interesting results. The refuse of 

 dredging for shells often yields mud, old shells, or algae; and 

 collectors will do well to secure such. Experience, however, 

 will teach the best places to look for recent diatoms; but the 

 above general directions will prove of service to those who are 

 new to the pursuit, or who collect for others. 



It should always be remembered that a knowledge of the 

 exact locality is of the greatest importance, — so that upon the 

 label should be written in ink the locality, date of collection, 

 and name of collector. Other facts deemed of interest may 

 also be added. 



HOW TO PREPARE SPECIMENS OF DIATOMACEM 



FOR EXAMINATION AND STUDY BY MEANS 

 OF THE MICROSCOPE, 



Having accumulated a number of gatherings of rough mate- 

 rial, which, a cursory examination has shown, contain speci- 

 mens of diatoinacese, and which, it is judged, it will answer to 

 clean and otherwise arrange and put up, or as it is technically 

 termed, "mount," for future study, the intending diatomist 

 requires to be informed how he may best set about preparing 

 his specimens in the most advantageous manner. The author 

 of the present sketch has published, in the seventh volume of 

 the Proceedings of the Boston (Mass.) Society of Natural History, 

 certain directions for collecting, preparing and mounting dia- 

 toinacese for the microscope; and as that paper contains a large 

 part of the information he desires to impart at the present time, 

 he will draw upon it pretty freely, supplementing it to ouch a 

 degree as later investigations warrant, or as may seem desirable. 



Although most of the published treatises on the use of the 

 microscope in general profess to give directions for mounting 



