Chemistry and Physies. 219 
obtained, hesperidin is a white, odorless and tasteless mass, con- 
oe of fine microscopic needles, insoluble in ether and nearly 
water. Alcohol takes up only ae quantities, though by 
distillation off of the solvent it may obtained in somewhat 
la ai needles. It fuses at 251° and deus oses, On analysis it 
ve the formula C,,H,,0,,. It possesses weak acid Pe ae is 
solabis | in alkalis and reprecipitate y acids. On heating with 
water and sodium amalgam for a few minutes, tiltering the orange 
solution and adding an acid, a precipitate falls‘ which dissolves in 
alcohol with a magnificent red violet color, with a blue violet 
fluorescence. By the action of dilute a seid KeapaHds 
apats into dextrose and hesperitin, C,, hhis ety the action 
S ovael 
acid OHO. Methyl- eapenettas | acid, oxidized by permanga- 
te, gives veratric acid ( imethylprotocatechnic acid). Acet- 
hesperetinic acid is identical with isoferulaic acid. From these 
reactions the author Orne the mpage as the rational formula of 
H=—CH-— CO— 
hesperetin : C,H, OHG) ae C,H, The quantity of 
hesperidin which is contained in the dried fruit, about 10 per 
cent, ere the importance of this glucoside to the nee of 
the e plan — Ber. Berl. Chem. Ges., xiv, 946, Apr , 1881. G. F. B. 
? Bice —Mever and 
note, and measurements ate yordiena he believes that the varia- 
tion in light-intensity of the dark lines will prove the most char- 
acteristic feature of the spectra of heavenly bodies.—Annalen 
der Physik und Chemie, No. 6, 1881, p. 338 
5. Intensity of Soun d.—OvERBECK has endeavored to obtain 
-quantitive measurements in acoustics by the use of the micro- 
phone. It is evident that if we posse a a epee ee 
electro-dynamometor an electrical mea of the intensity of 
sound waves could be obtained. In place of such an qiseteain dart 
Overt uses a galvanometer which is affected by the varying 
resistance of the microphone when the latter responds to sounds 
