Excerpt from Far Infrared Absorption in Liquefied Gases A special dewar, figure 2, was constructed to enable liquid cells to be held at predetermined temperatures. In all experiments liquid hydrogen was used as refrigerant in the inner container and a liquid cell was attached at the lower end Of the reflux tube a thin walled stainless steel tube passing through the refrigerant container. Variable thermal conductance between the refrigerant and the liquid cell could be Obtained by variation Of hydrogen gas pressure inside the reflux tube. The liquid cell was surrounded by a nitrogen-tempera ture radiation shield except for holes to allow the passage of the spectrophotometer beam. When liquid hydrogen was used as sample, a second hydrogen-temperature shield attached to the refrigerant bath was used. The outer vacuum jacket Of the dewar was fitted with thick polyethylene windows. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.