1. Readers of this communication may recall the experiment made in1885by Professor Thomas H. Norton, who, at my suggestion, studied the combinations that could be made between hydrastine and calcium. These, however, were altogether different from the compounds now under discussion.
2. Literature consulted gave me little information concerning the exact composition (physical included) of the material known as “fullers' earth.” Subsequent experiences have taught me that this is readily explained by the fact that the term “fullers' earth” is a blanket name, covering a multitude of different earth substances, of widely different composition. See Table IV.
3. Journal of the American Chemical Society,June, 1913.
4. Fullers' Earth, by Charles L. Parsons: “The shades of color of fullers' earth are fully as great as those of other kinds of clay. Most of the earths on the market are light brown, gray, buff, or cream color, and a few are almost white. All fullers' earths which have been found valuable for bleaching purposes show a distinct so‐called acid reaction. If a sample is touched to neutral litmus paper the paper will turn red; if the clay is suspended in water and phenolphthalein is added, a quantity of alkali, which varies widely with different earths, can be added before the red color appears. This property is no indication of true acidity, for the earth contains no acid.”
5. That this reaction was due to a something in the fullers' earth not yet understood was evidenced by the fact that no two qualities of fullers' earth were identical in their alkaloidal adsorption qualities, some possessing this in a marked degree, while others were very feeble, as shown by Table IV.