As the brownish powdery substance was mixed with the flat crystals produced above, a method had to be found to separate them and purify each. I screened them as much as possible with good results. I removed the last of the fine powder by dissolving it off with hot water. Metcalf said that they could be separated by their difference in specific gravity in fifty per cent alcohol but this method was unsuccessful. I boiled up the aqueous solution of the powdery substance with animal charcoal, filtered and evaporated to crystallization. Square, flat, white crystals were obtained identical in all but color with those mentioned above. They are soluble with difficulty in cold water, readily in hot, and insoluble in alcohol. In these properties and in appearance they compare to the ortho sulphonic acid of para toluidine as made and described by Parks, (Dissertation, 1892). Metcalf and Nevile and Winther say that the meta sulphonic acid of para toluidine forms needles, but I obtained nothing that could in any way be called needles. This sulphonic acid had no melting point, but charred and decomposed. A test for elements showed nitrogen and sulphur to be present. The aqueous solution had a strong acid reaction to litmus.
In order to see if this might be the desired acid I tried to prepare an acid chloride with phosphorus pentachloride in the usual way, and then intended to convert it into the amide and get a melting point for identification. I used equal weights of the acid and phosphorus pentachloride. I ground them together at ordinary temperature in a mortar: no result. I heated it on a water bath: no result. I heated it on a gauze over a flame: no result except decomposition and carbonization. However I poured water into the mixture and decomposed the excess of phosphorus pentachloride, and filtered. A gummy brownish mass remained which was insoluble in all reagents tried, (methyl and ethyl alcohol, benzine, petroleum ether, (40-60), water, carbon tetrachloride, dilute hydrochloric acid, acetone, and acetic acid.) Ethyl ether extracted a very small amount, just enough to color it yellow, and leave a yellow color on porcelain on evaporation, but not enough to make a study of the properties. On shaking up with concentrated ammonia the mass became very finely divided, but no solution appeared to take place; on filtering and evaporating to dryness there was no residue.