[E]. The ‘Analyst,’ January 1886, p. 16; ‘Chem. Zeit.,’ ix., 1886.
“Estimation of Saccharoid Matter; calculated as cane sugar.—The fermentation process was the one adopted, not that we consider it by any means a good one, but because it was the only one practicable. Fehling’s solution was inadmissible, owing to the precipitation of colouring and other matters, and the polariscope gave no indication. The objections to the fermentation process are due to the small amount of alcohol produced in the relatively large bulk of liquid. This renders the solution liable to acetification, and the ultimate distillate obtained is very weak in spirit, making it extremely difficult to obtain the correct specific gravity; the specific gravities obtained were always between ·998 and unity.
“We worked as follows:—200 grains of dried tumbeki were exhausted by repeated infusion in boiling water. The filtered liquid when cool was mixed with 100 grains of German yeast and allowed to stand three days in a warm place to ferment.
“About one-third was then distilled, the distillate being redistilled and three successive fractions of 500 fluid grains collected, the alcohol in each being estimated; the third portion contained little if any spirit.
“It being stated that basic acetate of lead removes saccharoid matter from the kindred plant tobacco; we tried its action on the infusion of tumbeki.
“At the onset it was found impossible to thoroughly wash the bulky precipitate caused by the lead; so, to ensure a definite result, sufficient basic acetate of lead was added to the infusion of 200 grains of tumbeki and the whole made up to 30 fluid ounces with distilled water and well mixed. An aliquot part (20 fluid ounces) was then filtered off, excess of lead removed by sulphuretted hydrogen, the sulphide filtered out, the solution boiled to drive off the sulphuretted hydrogen and the infusion, when cool, was fermented in the usual way. But acetic acid was necessarily present from the decomposition of the lead salt by the sulphuretted hydrogen, and this on distilling would tend to raise the specific gravity. To remedy this, slaked lime, or preferably potassic hydrate, was added before redistilling, but considering that from one to three per cent. of ammoniacal salt is contained in the original tumbeki, it is probable that some might still remain and by the action of the fixed alkali furnish a trace of free ammonia which would lower the specific gravity, and thus apparently raise the percentage of alcohol. As far as we can judge basic acetate of lead does not seem to remove fermentable matter from infusion of tumbeki.
| I. | II. | |||
|---|---|---|---|---|
| Pb treatment. | Pb treatment. | |||
| Ispahan | 2·64 | 2·67 | — | 2·35 |
| Hidjaz | 3·00 | 2·8 | 2·7 | — |
| Kechan | 5·58 | 5·33 | — | — |
| Shiraz | 3·48 | 3·88 | 3·23 | 3·1 |
“Ash.—The following bases and acids were uniformly found in the ashes:—Sodium, potassium, lithium, magnesium, calcium, iron, aluminium, silica, chlorine, phosphoric acid, sulphuric acid, carbonic acid.
General Table of Results.