1898.] MICROSCOPICAL JOURNAL. 83 



ond, the filtering material being- finer grained and the out- 

 come being 80 per cent of purification. The final liquids 

 were free from all odor and remained sweet if kept in open 

 or closed vessels. After the coarse matter was strained 

 out and buried, the subsequent purifications were believed 

 to be due to the work of aerobic organisms. 



Micrometer Measurer, — Curtis uses the one described 

 for the quantititive determination of silver. It is simple 

 and can be used with any microscope which has crossed 

 hairs in the tube or eyepiece. It consists of two metallic 

 plates, one above the other, to which a motion parallel to 

 one cross-hair can be given as well as across it. The two 

 are fastened upon a third plate which is attached to the 

 shell of the microscope. 



Wood. — Phosphorescence of decaying wood proves due 

 to minute vegetation and is not purely chemical as sup- 

 posed. The mycelium of a fungus from pine has been 

 cultivated in decoction of beech bark and Agar-agar, the 

 result being a white, brilliantly luminous growth. 



Crystals. — Tassin classifies them for microscopic exam- 

 ination under solution, sublimation, fusion. In the first 

 class, they are prepared from solution in a liquid by evap- 

 orating and cooling, by reaction of soluble compounds or 

 by chemical changes in general. To secure crystals by 

 fusion prepare a solution in molten magma or slowly cool 

 a homogeneous magma. Crystallization must proceed as 

 slowly as possible and the removal be effected when the 

 solution is at the minimum temperature. Crystals for 

 measurement are quickly and completely dried in order to 

 prevent corrosion or etch figures forming. 



Foraminifera. — 10,454 fossil forms were found in lyj oz. 

 of limestone from Cascina, Tuscany. They were so min- 

 ute as to require 500 to weigh one grain. An ounce of sand 

 from the Antilles was shown to contain 3,840,000 speci- 

 mens. 



Gold Nuggets. — The microscope shows that they have 

 been deposited from a solution around a nucleus. Etched 

 sections show crystallization, often large crystals with in- 



