CORBESPONDENCE. 275 



Extra Meeting of the Royal Microscopical Society. — We are 

 happy to say that the E. M. S. has determined to give an extra meet- 

 ing this year in July, and if found convenient, to continue it every 

 year for the future. We hope, therefore, that a good assemblage of 

 Fellows will prove to the Council that they are not mistaken in be- 

 lieving that the vacation is too long at present. The extra meeting 

 this year will be held on the second Wednesday instead of the first, 

 owing to the College being unable to spare the rooms on the first 

 Wednesday. 



Committee for Testing* Objectives. — This, which has been pro- 

 posed in a letter to us by Dr. Pigott, is favourably noticed in the 

 ' American Naturalist ' (May). We think that the writer's suggestion 

 is a good one. It is as follows : — As this subject is largely an inter- 

 national one, though not of sufficient importance to call for the meet- 

 ing of a committee representing the different countries chiefly inter- 

 ested, any movement, if made at all, in reference to it, should be a 

 concerted movement in England, Germany, France, if practicable, and 

 this country, the same lenses being sent for study from one country to 

 the other. Microscopists might thus be informed, not as to which 

 objectives are the " best," but as to which desirable qualities are pos- 

 sessed in an eminent degree by the lenses of the various makers. 



Eyesight and the Microscope. — Under this title there is a short 

 but useful pajjer in the ' American Naturalist ' for May. We merely 

 direct our readers' attention to it, as it is too long for quotation. 



Spore-cases in Coals is the title of a very valuable paper by Pro- 

 fessor Dawson, in the ' American Journal of Science ' (April). He 

 adds to his lectures, delivered in London, and to Professor Huxley's 

 well-known researches, some facts of interest. It is well to point out 

 that this subject was almost first investigated in this country by Pro- 

 fessor Morris, to whom the writer gives credit for his researches. 



COEEESPONDENCE. 



MouNTiNa Diatoms. 



To the Editor of the ' Monthly Microscopical Journal.^ 



Sir, — In the number 24 of the ' Monthly Microscopical Journal ' 

 Captain Knight exposes the difficulties which may be encountered by 

 those who wish to avail themselves of the method for selecting and 

 arranging symmetrically diatoms, as exposed by Captain Lang. 



If diatoms are rare, I should try butterfly's scales ; I may presume 

 to affii-m they are very good substitutes as objects, which being equally 

 interesting, permit one to acquire the greatest dexterity. I have 

 been successful beyond the most sanguine expectations, and I work 

 very easily with ^ power ( x 55 linear). 



VOL. V. X 



