Indeed, the authors are deeply indebted to these authors and 

 their book for much valuable information. 



We also wish to express our gratitude to all those 

 who have aided us in one way or another, especially to E. R. 

 Weinmann, Arthur Worischeck, Walter Brunberg and Dr. G. Orn- 

 sen who assisted in the proofreading. We shall be equally 

 grateful to those who bring to our attention such errors, 

 imperfections, and omissions as are inevitable in the first 

 printing of a work which is a pioneer in its field. A re- 

 vised and amplified edition is being planned for a future 

 date, and correspondence with the authors is solicited from 

 those wishing to co-operate in the compilation of a revised 

 text. 



The Twelve Acres, 

 Stone Ridge, N.Y. 



and 

 55 W. 42nd Street, 

 New York, 18, N.Y. 



August, 1946 



Bernard R. Regen 

 Richard R. Regen 



