90 



THE CONDOR 



Vol. X 



possible to file these slips under the vertical system unless they were enclosed in 

 something of uniform size. And last but not least the great ease with which any 

 desired data may be found in a vertical system of this kind makes it the handiest 

 system imaginable. 



Another idea which Mr. Dille has worked out is an "autograph data" blank, 

 which is of the same design as his regular blanks, but which he sends to collectors 

 who furnish him with sets and has them write the original data on his blanks but 

 over their own signatures, thus giving him the original data on uniform blanks. 



A tabulated register of all sets coming into and leaving the collection, which 



A SERIES OF THE EGGS OF THE AMERICAN CROW 

 SEIyECTED TO SHOW VARIATION 



gives the date, species, locality, collector, incubation, from whom secured and to 

 whom disposed, is also a great assistance in a well ordered collection, altho many 

 collectors seem to feel that this is superfluous. 



One might continue indefinitely to jot down the hundreds of little hints and 

 ideas that are produced by continuous experimenting, but I have covered the points 

 which have always given me the most trouble and I hope they may prove of benefit 

 to the reader interested in this line. 



Denver^ Colorado. 



