228 



NA TURE 



[yan. 2 1, 1875 



valves, the whole area being greater than that of any other sec- 

 tion of the column. Now, the question at issue is, whether by 

 this arrangement the semilunar valves bear any less pressure 

 because a ])ortion of the base of the column rests upon the vfall 

 of the ventficle. That they do not may be sufficiently proved 

 by the following considerations. 



It is a generalisation from Pascal's law that " when a liquid 

 enclosed in a vessel is submitted to an external pressure, every 

 plane surface that we cjn imagine in the interior of the vessel 

 experiences a pressure proportional to its area." As a conse- 

 quence of this law, it follows, if the force impressed upon our 

 imaginary surface represent the total force of reflux, that the 

 pressure sustained by the whole area of the base will be con- 

 siderably greater than the actual force of the column, and this 

 increase of pressure will be proportional to the difference between 

 the areas ol the two surfaces. Also, the pressure upon the semi- 

 lunar valves will be entirely independent of the pressure upon 

 the rest of the base, and will be directly proportional to their 

 own extent. It may be concluded, therefore, that whatever the 

 condition of things at the base of the aorta may be, no mechani- 

 cal advantage is gained thereby ; indeed, if the areaof the valves 

 be equal to that of the surface we have taken, they will sustain a 

 pressure equal to the total force of reflux of the column. Hence, 

 by extending the area of the base over the wall of the ventricle, 

 the only effect is to increase the total amount of pressure sus- 

 tained, without at all lessening the pressure upon its original 

 extent. 



It is true that if the aonic orifice contract with the muscular 

 substance of the ventricle, that in this way, i.e. by decreasing 

 the area of the valves, a varying amount of advantage would be 

 gained which would be greatest at the time of greatest contrac- 

 tion. This condition is, however, the only one that can at all 

 favour the idea that ''the reflux is most efficiently sustained by 

 the muscular substance of the ventricle," and as this condition is 

 doubtful, it must still seem that the main feature of Mr. Savory's 

 theory cannot be supported. W. Percy Ashe 



Phoenician Characters in Sumatra 



In a short communication to the Anthropological Institute in 

 December last (Nature, vol. xi. p. 199), Phoenician characters 

 were stated by me to be siill in use in South Sumatra. As many 

 of your readers may be glad to have more information on the 

 subject, I write to say that tlie district above alluded to includes 

 Rejang, Lemba, and Passammah, between the second and fifth 

 parallels of south latitude. Several manuscripts, on bamboo, 

 from this region are preserved in the library of the India Office ; 

 and a Rejang alphabet is given by Marsden in his " History of 

 Sumatra," third edition. Some of his characters, however, 

 appear to have been incorrectly copied. About half the Rejang 

 letters are admitted by ad the Oriental scholars to whom I have 

 shown them to be Phicnician of the common type ; others being 

 similar to forms found in Spain and other Phrenician colonies. 

 Most of the letters are tc-'cTSiJ, a peculiarity which is exi>lained 

 by the fact that the Rejing writing, according to Marsden, is 

 read from left to right, contrary to the practice of the Malays 

 generally. The matter is of great interest, and, it is to be hoped, 

 will be investigated by Phcciiician scholars. 



J. Park Harrison 



Ring Blackbird 



In my letter in Nature, vol. xl. p. iSy, I did not refer to the 

 Ring Ousel, for it did not occur to me that anyone woidd suppose 

 that, with the apparatus of so many standard works on birds, I 

 could fail to identify my bird, if he W'ere a Ring Ousel, male 

 or female. I therefore add that my bird is in no respect (save 

 the prevailing colour) like that species of Titrdiis. It is exactly 

 like a female blackbird, save that it has a white ruff, in the posi- 

 tion of the Barbaiy Dove's ring, and white spot under the chin. 

 I have never seen a Ring Ousel, or the picture of one, with those 

 characteristics. Besides, the Ring Ousel is migratory, and would 

 hardly be seen till the spring. 



Athenceum Club, Jan. 16 C. M. Ingi.ebv 



[Considering the time of year at which this specimen was 

 obtained, it is more probable that it is a pied variety of the black- 

 bird (which is far from uncommon) than a Ruig Ousel. If our 

 correspondent will forward the specimen to us, for examination, 

 we will settle the point for him, and return it. — Ed.] 



OUR ASTRONOMICAL COLUMN 



The Total Eclitse of the Sun on Ai'ril 6. — 

 Dr. Janssen's station for the observation of this eclipse is 

 mentioned as probably Hu(f, the position of which place, 

 as laid down on the Admiralty Chart of Cochin China, is 

 in longitude 107* 38' east of Greenwich, and latitude 

 16° 29' north. For this point the Nautical Almanac 

 elements give the following figures : — 



First contact at ih. 38m. 6, local mean time, 130° from 

 the sun's N. point towards the west, for direct image. 

 Totality begins at 2h. 57m. 2s., and continues 3m. 12s., 

 the sun at an altitude of 46^ 



Encke's Comet will no doubt be within reach as the 

 moon withdraws from the early evening sky. The posi- 

 tions subjoined are reduced to 8h. Greenwich time from 

 the cphemeris of Dr. von Asten, of Pulkova, published by 

 the Academy of Sciences of St. Petersburg : — 



R.A. N. I'.D. DISTANCE, 



h. m. s. . , 



i875~Jan. 24 23 23 31 85 40-6 1-989 



„ 25 — 24 53 85 32-9 



,, 26 — 26 16 85 25-0 



,, 27 — 27 40 85 17-0 



„ 28 — 29 6 85, S-S 1-977 



,, 29 — 30 33 85 0-4 



„ 30 — 32 2 84 51-9 



,, 31 — 33 31 84 43-3 



Feb. I — 35 2 84 34-5 I -961 



„ 2 — 36 34 84 25-5. 



,, 3 — 3S S 84 164 



., 4 — 39 43 S4 7-1 



,, 5 23 41 20 S3 57-6 1-940 



Mr. Otto Struve writes that Dr. von Asten's calcula- 

 tions show the last three revolutions of this comet can be 

 perfectly represented by a uniform mean motion, without 

 the hypothesis of a resisting medium, and even with 

 greater precision than all the previous observed returns 

 with that hypothesis. At the same time, during more 

 than one revolution, something like acceleration has been 

 indicated, and nearly to the same amount as Encke had 

 supposed. This was the case between 1862 and 1865. 

 Again, in other revolutions, as between 1S45 and 1848, 

 the acceleration has been subjected to very considerable 

 changes. In the actual state of his researches Dr. von 

 Asten is inclined to conclude that the existence of a 

 resisting medium is not proved by the motion of Encke's 

 comet, and that the observed acceleration in several 

 returns ought to be attributed to the action of other 

 forces ; for instance, repulsive power produced by the 

 approach of the comet to the sun, the effect of which 

 might vary considerably, according to the conditions in 

 which the return to perihelion takes place. A short 

 paper by Dr. von Asten on this interesting subject is in 

 the press. 



Winnecke's Comet of Short Period, last visible 

 in 1S69, will also be observable in the morning sky from 

 about the next new moon. The ephemeris calculated by 

 Prof. Oppolzer of Vienna will be found in No. 2,016 of 

 the Astronoiiusclie Nachrklitcii. This comet will pro- 

 pably be faint, while it remains visible at the present 

 return. It arrives at perihelion on March 12, and at its 

 least distance from the earth on February 15. It is 

 Comet 1819 (3), and Oppolzer thinks he has identified it 

 with one of the imperfectly observed comets in 1S08. 

 The elements which have been determined for 1875 show 

 that the comet now makes a very close approach to the 

 orbit of Jupiter; indeed, in heliocentric longitude 109° 25', 

 the distance between the two orbits is less than o 06 of 

 the earth's mean distance from the sun ; this point is 

 passed rather less than two years before perihelion pas- 

 sage. So far as can be judged at present, the comet will 

 not be liable to great perturbation from the attraction of 

 Jupiter till the year 1907, when it is possible a complete 



