ACKNOWLEDGMENTS 



During the progress of my investigations on microtechnique, 

 I received helpful suggestions from my colleagues, Professors 

 A. B. Wallgren, Alexander Lowy, and J. K. Miller. Dr. Russell 

 Gottschall and Dr. Primitivo Colombo made many of the prelimin- 

 ary tests on coal-tar dyes. Dr. Anna Mary Carpenter ably assisted 

 in a number of ways, especially in the preparation of the manu- 

 script. I am greatly indebted to the several directors of the tech- 

 nological laboratories of both E. I. du Pont de Nemours and Com- 

 pany, Wilmington, Del., and the National Aniline and Chemical 

 Company, Philadelphia, Pa., for data on color technique and for 

 samples of mordant, sulfur, and vat dyes. 



William H. Emig 



University of Pittsburgh 



March 31, 1941 



