NOTES. 103 



one-fifth of the species extant have yet been characterised or 

 enumerated. In this view of the case the species in our collec- 

 tions, whether described or undescribed, do not represent perhaps 

 more than one-fifth of the whole. In other words, to say that 

 there are 10,000,000 species of insects in the world, would be, 

 in my judgment, a moderate estimate." 



The American Microscopical Society offer the following prizes 

 for the encouragement of microscopical research : — 



Two prizes of 50 dols. each for the best papers, and two prizes 

 of 25 dols. each for the next best, which give results of an original 

 investigation on animal and plant life respectively, made with the 

 microscope. The papers are not to be less than 3,000 words in 

 length and the methods by which the results were obtained must 

 be given in full. Two prizes of 30 dols. and 15 dols. each for the 

 best and next best six photomicrographs on the same subject in 

 animal or vegetable histology. The photomicrographs are to be 

 of the following amplications, viz. : 50, 150, and 500, two of each. 

 They are to be made by transmitted light and printed on albumen 

 paper from untouched negatives. Two prizes of 30 dols. and 

 15 dols. each for the best and second best six lantern slides, illus- 

 trating some one biological subject. The slides must be accom- 

 panied by a full description of the methods of preparation of the 

 specimens. The photographs and slides are to become the pro- 

 perty of the Society. The papers, etc., must be submitted to the 

 Committee before July ist, 1893. The competition is open to 

 members of the Society and to those who make application for 

 membership before submitting their papers. The entrance and 

 annual fees are 3 and 2 dols. respectively. All further particulars 

 can be obtained of the Secretary, Prof. \V. H. Seaman, 1424, 

 Eleventh Street, Washington. 



At the opening meeting of the R.M.S., Mr. G. C. Karop des- 

 cribed a microscope made of aluminium by Messrs. Swift. With 

 the exception of a microscope which had an aluminium stage, 

 shown in the United States some months ago, we believe it is the 

 first instrument practically made entirely of that metal. Of course, 

 its extreme lightness is the chief characteristic, the weight being 

 2 lb. 13 oz., against 7 lb. 10 oz. of an exactly similar instrument 

 made in brass. The adjustments and screws were the only parts 

 in which aluminium was not used on account of certain difficulties 

 inherent to that metal. 



