56 THE MICROSCOPE. April 



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potassium acetate is removed, the yellow lead chromate 

 washed on a filter. It is drained until it is a mOist pow- 

 der, uot dry, aud then is added to the Gum Thus solution 

 in alcohol, in excess, and boiled by means of a water bath 

 for about fifteen minutes. The solution is left to stand 

 until cool and the excess of lead chromate permitted to 

 settle. We have then the mounting material. 



Preparing the phosphorus solution for mounting is 

 done in a different way. Procure some pure phosphorus. 

 Remember that it is inflamable, and, besides, the burns that 

 it makes are extremely painful. It is also poisonous, so to 

 prepare it we work with it under water handled with a 

 forceps, not by the hand at all. Some is put into a flask and 

 cold water added. It is then held over the flame of a lamp 

 until the phosphorus melts. Immediately it is taken from 

 the flame and violently shaken. At the same time cold 

 water is added. In this way the phosphorus is broken up 

 and concretes into fine sand-like phosphorus in particle of 

 the sand being spherical. When it is cold, a few grains 

 of the sand ai'e collected by a pipette and transferred to 

 another vessel. Here the water is nearly poured ofl" aud 

 oil of cinnamon added in enough quantity to just cover 

 the phosphorus. It is then heated, not boiled, and some 

 of the phosphorus dissolves. It is then added to the solu- 

 tion of Gum Thus in alcohol and we have the solution of 

 phosphorus for mounting. 



Sulpliur can be dissolved in the same way and quini- 

 dine also. All of these make valuable mounting solu 

 tions and I hope for their introduction into microscopy, 

 for I feel that we have here solutions of interest and 

 shall look for the results with interest. 



Louis Agassiz. — Another biography, of G20 pages, has been 

 issued to record the life of this naturalist. This time Mr. Jules 

 Marcou is the biographer who says that the previous lives were 

 too eulogistic. The review of this book by Nature, however, 

 is far from eulogistic of what Marcou has written. It is very 

 spicy. 



