ID#: 8639
Caption:
This historic 1935 diagram, which had been digitally enhanced, depicted three renderings of properly constructed overlapping type manhole covers. Manhole covers were found to be quite important to maintaining safe and secure sanitation systems. This was one of a series of instructional drawings used by the Minnesota Board of Health to train its state public health workers. The focus of this image, was on protecting potable water supplies from bacterial contamination, due to incorrect disposal of waste, which might foul ground water, rivers, lakes, and streams. The specific citation was, “Minnesota State Board of Health, Division of Sanitation, Water Supplies and Sewerage Systems for Country Homes, 1933, p. 34”.
High Resolution: Click here for hi-resolution image (22.86 MB)
Content Provider(s): CDC/ Minnesota Department of Health, R.N. Barr Library; Librarians Melissa Rethlefsen and Marie Jones
Creation Date: 1935
Photo Credit:
Links: Minnesota Health Department
Minnesota Health Department; R.N. Barr Library
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Copyright Restrictions: Permission is not required for public domain images, however, these images are provided by CDC and are available for personal, professional, and educational use with appropriate attribution. Redistribution must credit CDC and, where known, the individual photographer, and identify the CDC website as the free source. For additional terms see Use of Agency Materials | Other | CDC