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THE POPULAR SCIENCE MONTHLY. 



ultimately the fundamental note or a single 

 vibration was exhibited. Very high har- 

 monies were shown by means of a very 

 flexible string with a high velocity dividing 

 the revolving tape into very numerous 

 equal segments of vibration, or, as the pro- 

 fessor preferred to call them, harmonics. 



Petroleum In Santo Domingo. In a note 

 to the Mechanics' Magazine, Mr. William M. 

 Gabb describes a petroleum-spring situated 

 three miles north of the town of Azua, in 

 Santo Domingo. It is near a stream, the 

 name of which signifies "stinking water." 

 The spring makes its appearance as a stag- 

 nant, torpid pool, exuding slowly through 

 a heavy gravel-deposit. A very small area 

 in the vicinity is covered with deposits of 

 pitch, and, for half a mile down the dry bed 

 of a rain-water stream, the gravel and sand 

 are more or less cemented by an impure 

 pitch, sometimes plastic, oftener hardened 

 to asphaltum. The water is colored a dirty 

 brown by the presence of the oil. Jets of 

 gas bubble up at different points near the 

 spring. The gas is not inflammable, and has 

 more of a fetid than kerosene odor. In ap- 

 pearance and mode of occurrence the spring 

 strikingly resembles those of Trinidad and 

 California. It is the only spot on the island 

 where bituminous products are found. 



Photographing the Eye and Ear. Dr. 



Vogel writes to the Philadelphia Photog- 

 rapher as follows: "That the interior of 

 the human eye has been photographed is 

 well known. The experiment is a some- 

 what cruel one for a living subject; still 

 there are victims who stand it. I know, 

 for instance, a very handsome young lady, 

 whose brother is a physician, who patiently 

 takes extract of belladonna until the pupil 

 has become sufficiently enlarged ; the in- 

 terior of the eye is then illuminated with 

 magnesium-light, and photographed. In a 

 similar manner has the ear been photo- 

 graphed, that is to say, the tympanum only. 

 A tube is inserted, in which is a mirror 

 inclined at a certain angle. The mirror 

 throws light into the interior of the ear. 

 The mirror is also provided with a central 

 hole through which the illuminated tym- 

 panum can be inspected. A system of 

 lenses projects an image on the sensitive 



plate, and the picture is made in the ordi 

 nary manner." 



Chemical Influence f Light. In a re- 

 cent lecture on the chemical action of light, 

 Prof. Koscoe gives some interesting facts 

 concerning the chemical effects of sunlight 

 at different times of the day, and in differ- 

 ent atmospheres. The number of chemi- 

 cally-active rays vary throughout the day. 

 Their maximum is always highest at noon. 

 The curve of the heating rays reaches its 

 highest point after noon, but this is not the 

 case with the chemically-active rays. The 

 chemical intensity appears to depend solely 

 on the height of the sun in the heavens, and 

 at the same distance from noon ; on either 

 side it appears to be equal. The chemical 

 power of sunlight also varies with the place. 

 Prof. Eoscoe gives the results of measure- 

 ments at Kew, Lisbon, and Para. At Kew 

 the intensity was 94.5, at Lisbon 110, and 

 at Para 313. An opalescent atmosphere 

 appears to cause the absorption of a large 

 number of the chemically-active rays. 

 Hence the important advantage, in point 

 of vegetation, which those countries have 

 where the atmosphere is clear. 



The Leaf a Vicarious Organ. Some 

 interesting experiments have lately been 

 conducted by M. Calliet, to determine the 

 precise action of plant-leaves in the ab- 

 sorption of water in the liquid form. They 

 have led him to the conclusion that leaves 

 do not absorb water while the roots are 

 supplied. But when the ground is too dry 

 for the roots to obtain it, if water be put in 

 contact with the leaves, they will absorb it 

 for the nourishment of the plant. The ex- 

 perimenter thus educes the fact that the 

 action of the leaf .is a vicarious and not a 

 natural function. 



Carbolic Acid from Plants. M. Brougk- 

 ton, government chemist, attached to the 

 cinchona-plantations of Ootacamund, in 

 India, has obtained carbolic acid from the 

 Andromeda Leschmantii , a plant which 

 grows there abundantly. The product is 

 less deliquescent than that obtained from 

 coal-tar, and, owing to the expense attend- 

 ing its preparation, is not likely to compete 

 with the article at present in the market. 



