192 -/. .'/. Blake — Plotting Crystal Zones on Paper. 



When tlic exact laws on which crystal architecture is based 

 are definitely determined, we may see a way to condense 

 crystal descriptions and still retain the essentials. Some 

 crystal descriptions retain the skeleton but lack the substance. 



We have shown how, by means of a single circle goniometer 

 and a few simple tools, we can get interesting results in study- 

 ing crystals. There are means of facilitating this crystal work 

 still further, and by their use we may follow this partly ex- 

 plored field with good prospects of securing valuable results. 

 The act of partially measuring a large number of species, and 

 storing away sometimes very bare details, does not advance 

 the science in a way we could wish. , 



Only a comparatively few out of a very large number of 

 subjects have been tested by these methods tip to this time, 

 but every species appears to present some interesting features 

 of its own. 



New Haven, Conn., Aug. 1916. 



