Journal of the Asiatic Society of Bengal Part II Physical Science 1873

The nature and arrangement of the littering materials in the filtering tanks at Palta were decided upon chiefly from the results and conclusions to which I came after a series of experments made during the rainy seasons of 1863 and 1869 for the purpose of ascertaining what was likely to be most suitable and efficacious for filtering the muddy water of the Hugli during the floods that extend fr [...] Tho printiples of sand-filtration were appealed to and these wore explained to depend chiefly on the attractive power of the coarser particles of sand for the finer particles of the mud suspended in the water ; and this was represented as the' most important part of the process — such in fact filtration "--apparently almost to the exclusion of what was called mere straining. [...] The most important part of the process is straining the prevention of the passage of particles through narrow crevices between the grains of sand ; next is depo:"212 D. WeIdie—On the Muddy Water qf the [No. [...] 215 so to change the character of the mud in the river water of the rains as to enable it to settle with sufficient readiness and in suds a state as to render the water capable of being filtered without difficulty ? Will the difFerence of quantity between that of the saline matter which exist.; in the water of the rainy season and that say of December be sufficient ? Will the. [...] The following table includes a few of the preceding substances most likely to be of practical applicftion :— Table of absolute quantities of substances necessary for the clarification of 1 million gallons of muddy water of the Hugli during the rainy season calculated from the data given above.