318 LATOUCHE: GEOLOGY OF NORTHERN SHAN STATES. 



clays are exposed to the air and become dry they crumble into 

 dust, while the lignite splits into cubical fragments like a piece of 

 rotten wood. A collector, therefore, should be equipped with some 

 means of hardening the specimens on the spot, either by soaking 

 them in varnish or otherwise. 1 



1 Mr. Tipper tells me that he has found the following method of hardening these 

 fossils very successful. The specimen, cleaned as far as possible from adhering 

 matrix, is first soaked in a solution of silicate of soda, - water glass,' and then in 

 one of chloride of calcium ; it is then thoroughly dried, and painted over either 

 wjth Canada balsam or with hard white copal varnish. 



