_Reagent._—Prepare a dilute cream of asbestos fibre which has been
finely shredded, thoroughly ignited, treated with strong hydrochloric
acid for at least 12 hours, and washed with distilled water till free
from acid.
_Procedure._—1. Prepare a mat of the asbestos fibre 1/16 inch thick in a
Gooch crucible. Dry it in an oven at 103 or 180° C., cool and weigh.
Filter 1,000 cc. of samples having a turbidity of 50 parts per million
or less. If the turbidity is higher use sufficient water to obtain 50 to
100 mg. of suspended matter. Dry for one hour at 103 or 180° C., cool
and weigh. Report the temperature at which the residue was dried. If
1,000 cc. is filtered the increase in weight expressed in milligrams is
equal to parts per million of suspended matter.