1894 THE MICUOSCOPE. 177 



is equivalent to presenting them with a year's subscription 

 if they buy one of these splendid little instruments. The 

 instrument will go direct from the factory to the sub- 

 scriber in a nice little box and is guaranteed by the 

 maker to be in perfect order. 



Whoever can get us five new subscribers prepaying 

 one dollar each for 1895 will receive one of these micro- 

 scopes as a premium free of all cost. The name of this 

 instrument is the Excelsior Microscope. 



Aquariums for Microscopists. 



By M. J. TEMPERS, 



PARIS. 



Translated from Le Micrograph Preparateur. 



For nearly eight years, I have had upon two of my 

 tables, one facing the North and the other the West, 

 half a dozen small aquariums, in four of which, water has 

 not been completely changed but twice, and in the two 

 others but four or five times during that period. 

 • I have noted from time to time all the different micros- 

 copical organisms which developed in them and of which 

 the number amounts to almost three hundred. Consid- 

 ering the years and especially what I have occasionally 

 introduced in them, I have been able to grow certain 

 organisms in quite an important quantity and in the best 

 possible conditions. 



The number of species of Diatoma-cese, of filamentous 

 Algge, of Desmidiacese and of Infusoria were greatest; then 

 come the Larvae, the Worms, the Entomostraca, etc. 



The pleasure and interest which can be found in 

 following the developement of such a great number of 

 interesting objects, cause me to believe that many of 

 our readers will try to do as I have done. As will be 

 seen, nothing is easier. My aquariums contain — one a 

 litre and the other half a litre. They are simply right- 



