This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...of filtered samples are usually from one to five parts per million too low. A very small amount of suspended matter in the sample causes a relatively great error by apparently increasing the intensity of the color. Transfer a portion of the clear filtrate to a tall 100 cc. Nessler tube or colorimeter cylinder. ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...of filtered samples are usually from one to five parts per million too low. A very small amount of suspended matter in the sample causes a relatively great error by apparently increasing the intensity of the color. Transfer a portion of the clear filtrate to a tall 100 cc. Nessler tube or colorimeter cylinder. Compare with the color standards described above. "The color of a sample shall be observed by filling a standard Nessler tube, to the height equal to that in the standard color tubes, with the water to be examined. The observation shall be made by looking vertically downward through the tubes upon a white surface." 1 1 Such a series will be found upon the laboratory reagent shelves, hence neither standard nor dilutions need to be prepared by the students. 1 Standard Methods of Water Analysis. American Public Health Association. Should the color of the sample be found to be greater than 70, dilute with distilled water. After determining the color of a filtered sample preserve the filtrate for the determination of solids in suspension, see page 54. The results of color observations are to be expressed in whole numbers as follows. "Color between 1 and 50 recorded to nearest unit. Color between 51 and 100 recorded to nearest 5. Color between 101 and 250 recorded to nearest 10. Color between 251 and 500 recorded to nearest 20." Determination of Color icith V. 8. Geological Survey Color Tubes and Glasses. "Color Standards. Disks of colored glass have been prepared as standards for measuring color of water in the field. These disks have been rated to correspond with the platinum-cobalt standard. The color is measured by balancing the color of the water in a metallic tube with glass ends against the colors of glass disks of known value. The number...
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