hook shown just above the plate B is to hold an and there seems to be no reason whatever for adopting though there is no reason why it may not be made incandescent light for artificial illumination. a different standard unit which is as arbitrary as ours, larger. The diffraction photograph is a… … When your expert on concrete construction next dis- ’*Cement Materials and Industry of the United States” VIEWING END OF THE DIFFRACTION CHROMOSCOPE, cusses his specialty, please let him take up the practi- is by Edwin C. Eckel. “Electricity in the Home” is a cability of using concrete or armored…
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