MAKING BLUE PRINTS 513 



schools the students will not have sufficient time to make 

 up their own blue-prints. Much time may be saved in print- 

 ing if very large frames (two feet square or larger) are 

 used since the whole frame can be filled and printed at one 

 time. The instructor should see that blue-prints are made 

 only from typical and satisfactory records, and each print 

 should be made as small as possible to include the required 

 portion of the record. Copies of kymographic records may 

 also be printed on regular photographic printing paper and 

 developed and fixed in the usual manner. This is more ex- 

 pensive but is often available for special work. 



