Adsorption

Abstract

“THE above effects, however, become of consequence in those frequent cases in which a muddy liquid is only partially filtered through a dry filter in order that some analytical estimation may be made in a given volume of the filtrate. The first drops of the filtrate must therefore be discarded.” The above quotation is from Ostwald's “Foundations of Analytical Chemistry” (English translation), the italics being in the text. Ostwald makes this a purely theoretical deduction, but the practice of discarding first drops does not, I think, originate with him. Doubtless many analysts neglect the precaution, but many use it.