This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book. ++++ The below data was compiled from various identification fields in the bibliographic record of this title. This data is provided as an additional tool in helping to ensure edition identification: ++++ The Manufacture Of Optical Glass And Optical Systems: A War-time Problem. May, 1921 United States. Army. Ordnance Dept, Frederic Eugene Wright Govt. Print. Off., 1921 Glass manufacture; Optical glass; Optical instruments | The Manufacture Of Optical Glass And Optical Systems by United United States Army Ordnance Dept, Paperback | Indigo Chapters