Incidentally the following points were also established:—The solubility of the phloroglucide, under the conditions of finally separating in a condition for drying and weighing, is 1 mgr. per 100 c.c. of total solution, made up of the original acid solution, in which the precipitation takes place, and the wash-water required to purify from the acid. The phloroglucide is hygroscopic, and must be weighed out of contact with the air. The presence of diresorcinol is without influence on the result, provided a sufficient excess of actual phloroglucinol is employed. Thus even with a preparation containing 30 p.ct. of its weight of diresorcinol the influence of the latter is eliminated, provided a weight be taken equal to twice that of the furfural to be precipitated. The phenol must be perfectly dissolved by warming with dilute HCl (1.06 sp.gr.) before adding to the furfural solution. For collecting the precipitate of phloroglucide the author employs the Gooch crucible.
The paper contains a large number of quantitative results in proof of the various points established, and concludes with elaborate tables, giving the equivalents in the known pentoses and their anhydrides for any given weight of phloroglucide from 0.050 to 0.300 grm.
UEBER DEN PENTOSAN-GEHALT VERSCHIEDENER MATERIALIEN.
B. Tollens and H. Glaubitz (J. für Landwirthschaft, 1897, 97).
ON THE PENTOSANE CONSTITUENTS OF FODDER-PLANTS AND MALT.
(p. 171) (a) The authors have re-determined the yield of furfural from a large range of plant-products, using the phloroglucol method. The numbers approximate closely to those obtained by the hydrazone method. The following may be cited as typical:
| Substance | Furfural p.ct. |
| Rye (Göttingen) | 6.03 |
| Wheat (square head) | 4.75 |
| Barley (peacock) | 4.33 |
| Oats (Göttingen) | 7.72 |
| Maize (American) | 3.17 |
| Meadow hay | 11.63 |
| Bran (wheat) | 13.06 |
| Malt | 6.07 |
| Malt-sprouts | 8.56 |
| Sugar-beet (exhausted) | 14.95 |
(b) A comparison of wheat with wheat bran, &c. was made by grinding in a mortar and 'bolting' the flour through a fine silk sieve. The results showed:
| Furfural p.ct. | |
| Original wheat | 4.75 |
| Fine flour | 1.73 |
| Bran (24 p.ct. of wheat) | 11.25 |
| Wheat-bran of commerce | 13.06 |