ae longer. erty a Pebinsiderabts ecante of ata senicn brane will ete 
As ‘soon as the liquid is neutralized, 50 cc. of N/2 potash lye are added; one then 
~ boils it for two hours under a reflux condenser, cools quickly and titrates the excess 
= of alkali with with N/2 hydrochloric acid. There is far more phenolphthalein necessary 
Be than in ordinary titrations. If 100 grams of oil be used, the number of cc. of N23: 
~ potash lye consumed multiplied by 0.098 and the factor 1.28 will indicate the percentage 
3 of saponifiable substances, calculated as linalyl acetate. 
__ As aldehydes are disturbing in this estimation, they are removed with the aid of 
_ semicarbazide hydrochloride. It resulted to be useless to filter off the citral semicar-— 
_ bazone, as one does not succeed in making the deposit of semicarbazone absolutely 
free from esters. The presence of the citral semicarbazone does not disturb the saponi- 
fication; it does not use up any alkali, as has been proved by experiments. In order 
to obtain correct figures, the percentage of linalyl acetate must be multiplied by 1.28. 
+ The method was tried as to its reliability on mixtures of known composition. In 
- genuine lemon oils, ester contents from 1.24 to 1.74 per cent. were found in this way. 
be expected to waste 100 grams of either lemon or orange oil on each single estimation 
of esters which, by the way, is of secondary importance and may be carried out in 
_ case that it does not influence the ester v. to an extent worth mentioning. The presence 
= the best success in the ordinary way. 
Be intensely yellowish red colour appeared on mixing solutions of vanillin and sulphanilic 
acid. He went further into the matter and found that he had to deal with a condensation 
In our opinion this proceeding is not called upon to acquire many friends. Quite — Se 
apart from the fact that it abounds with possibilities for errors, nobody can seriously _ 
the usual manner and with only 1.5 gram of oil exactly enough to show whether the — < - 
oil tested has a normal ester v. or not. The content of aldehydes is so small in either —_ 
_ of waxy matter does not interfere either, oil of bergamot being the best proof for this x a3 
assertion, as the estimation of its ester v. has for long enough been carried out with oe 2 
The presence of some aldehydes proved by means of sulphanilic and naphthionic acids. a 
_ When studying the colour reactions of vanillin, E. P. Haussler?) observed that an 
3 product of both components, presumably a benzylidene compound. P. Pooth®), who, — 
Ss owing to an-agreement with Haussler, took up the study of analogous condensation — 
_ products of aldehydes and sulphonated aromatic amido compounds, succeeded in con- 
firming Hiaussler’s supposition by proving that the condensation product of vanillin | * 
Be great advantages for qualitative purposes, as then said reactions are still more distinct. 
_ off for a closer investigation. 
_ Pooth carries out the reaction as follows: 3 to 4 cc. of a 10 per cent. neutralized 
-_ agueéous solution of the sodium salt of the sulphonic acid are heated in a porcelain dish 
ona water-bath. - The aldehyde or the mixture, dissolved in 96 per cent. alcohol, are 
_ then added quite hot, when the colouring will take place immediately. It generally 
= becomes more intense on evaporation. The same is the case very often, if a few 
eee 1) See Report October 1910, 163. — *) Zeitschr. f. anal. Chem. 58 (1914), 363, 691; Report April 1915, 
61. — %) Schweiz. Apotheker Ztg, 54 (1916), 377. 
‘ really is a benzylidene compound. Although the colour reactions of sulphanilic acid 
and aromatic aldehydes are very well noticeable, the use of naphthionic acid offers 
In most cases the reaction product parallizes on cooling and may then be separated 
