There is such a wealth of material available from which a bibliographie of facsimile may be compiled that it is quite impossible to include in one brief rÃ©sumÃ© all such material and references.
The many patents and publications which have been referred to herein have been selected for convenience of the thirties and later reference, and because of the belief that they represent illustrate examples of the several forms of apparatus considered.
However, in view of the illustrative nature of the several citations, no inferences can or should be drawn from the inclusion of any reference as to either its possible breadth or its possible domination of the field whith which it has been mentioned nor should the omission of citation be considered as indicating any lack of importance.
Acknowledgment is due all of the technical and other publications used as a source of reference material.
(C) Marius Rensen