The action of mercuric acetate on the methyl ethers of coumarinic and coumaric acids and their 5-nitro derivatives has been described. The first two undergo addition at the double bond as well as mercuration and the compounds have the carboxylic formula. The nitrocoumarinic and coumaric acids undergo addition only and yield the carboxylic form in the cold and the anhydro form on heating. When the addenda are eliminated by the action of dilute hydrochloric acid the change is accompanied by geometrical inversion fromcis totrans. The results so far obtained with cinnamic acid and its derivatives are reviewed.

The lichenRoccella montagnei collected in Waltair has been found to differ markedly in composition, depending upon the season. Erythrin, Erythritol, Lecanoric acid, Roccellic acid and Orcinol are the main components besides isolichenin. The present findings differ from previous work in that erythritol and roccellic acid are now found in this lichen whereas oxyroccellic acid is absent. The constitution of erythrin as the erythrityl ether of lecanoric acid is supported.

The isolation of a new phenolic compound, ‘Montagnetol’ from the lichenRoccella montagnei and its properties are described. The details of the extraction of a sample of the lichen which contained it as the major component are given.

The constitution of montagnetol has been established as the erythrityl ester of orsellinic acid for the following reasons: (1) it gives the homofluorescein reaction slowly, (2) 5-hydroxy-4: 7-dimethyl coumarin could be obtained as a product of its condensation with ethylacetoacetate under the conditions of Pechmann’s reaction, (3) decomposition with hot dilute sulphuric acid or with hot baryta produces orcinol and erythritol, (4) concentrated sulphuric acid at 0° gives orsellinic acid and erythritol, (5) hot methyl alcoholic potash coverts it into methyl orsellinate and erythritol, and (6) by the action of diazomethane followed by methyl acloholic potash dimethyl ether of methyl orsellinate is obtained.

Alower melting sample of montagnetol has been isolated fromRoccella montagnei. It gives all the reactions of montagnetol, but differs in having a lower melting point and a different crystal structure, and in being dextrorotatory. Hence it is identified asd-montagnetol. The higher melting compound is the racemic variety having no optical activity. The general lesults indicate that racemisation takes place even in the plant.

The constitution of erythrin has been definitely established. The new important observations now made are as follows: (1) it is not a carboxylic acid; (2) it is optically active; (3) picroerythrin is identical with montagnetol; (4) trimethyl erythrin a compound in which all the phenolic hydroxyl groups are methylated is obtained by the action of diazomethane; (5) on hydrolysis with alcoholic potash the methyl ether yields the ester of dimethyl orsellinic acid and the ester of isoeverninic acid. Consequently, it is concluded that erythrin is the erythrityl ester of lecanoric acid. This is in agreement with the occurrence of lecanoric acid and montagnetol along with erythrin in the lichens.

Detailed chemical examination of the roots ofDerris cuneifolia has been carried out. No rotenone could be obtained but a new crystalline compound could be isolated and is named ‘Cuneifolin’. It has the molecular formula C₂₄H₂₄O₅ and contains an alcoholic hydroxyl group and a ketonic group.

Stokes’ and Seth’s solutions for the slow motion of a sphere in a viscous, incompressible liquid have been discussed from the viewpoint of the structure of the velocity field and its relation to the drag of the sphere. The problem is analysed from a different angle in this paper. It is believed that it throws more light on thephysics of the problem.