Methods for close automatic control of incubating temperatures in laboratories . Fi<3. 1.—Chart showing drop in room temperature for one week, with heat supply entirely shut off. Directly on the expanded metal a J-inch course of cement mortar wasapplied, mixed in the proportion of 1 part of Portland cement to 2l^artg clean, sharp sand. While the mortar was green a course of 2-inch cork board waserected on it and the joints were slushed with hot asphalt. Againstthe exposed surface of the cork board a Portland-cement plasterfinish about one-half inch in thickness was applied in two
Methods for close automatic control of incubating temperatures in laboratories . Fi<3. 1.—Chart showing drop in room temperature for one week, with heat supply entirely shut off. Directly on the expanded metal a J-inch course of cement mortar wasapplied, mixed in the proportion of 1 part of Portland cement to 2l^artg clean, sharp sand. While the mortar was green a course of 2-inch cork board waserected on it and the joints were slushed with hot asphalt. Againstthe exposed surface of the cork board a Portland-cement plasterfinish about one-half inch in thickness was applied in two first coat, about one-fourth inch in thickness, was mixed in the 4 , BULLETIN 951, U. S. DEPARTMENT OF AGRICULTUEE. proportion of one part Portland cement to twosand, and it was rough scratched. After this. parts of clean, sharpcoat had thoroughlydried, the secondcoat, approxi-mately one-fourthinch in thicknessand mixed in theproportion of onepart of Portlandcement to one andone-half parts ofclean, sharp sand,was applied a-ndbrought to a floatfinish. Shelves.—Shelveswere originally con-structed (fig. 2) of1-inch galvanized-metal pipe, coveredwith galvanized-wire mesh made ofXo. 16 wire withfour meshes to theinch. The wiremesh was securelysoldered to the pipeframe, care beingtaken to leave noprojections thatmight cut or scratchthose worldng int h e was found, how-ever, that the wire-mesh covering of-fered more or lessresistance to plac-ing the trays onthe shelves, and itwas subsequentlyremoved and thetrays containingthe flasks are nowplaced directly onthe pipes. All thetrays containing the CONTROL OF INCUBATING TEMPERATURES IN LABORATORIES 5 flasks are of the same size and fit on the pipe frame. Where different-sized crates are used, however, the wire covering- is advisab
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherwashi, bookyear1921
