6 



MODE OF CONSTRUCTING TELEGRAPHS IN INDIA. 



[1853 



border and tlic centre of the sun, and also in some respects by 



the zodiacal light, so perceptible in our climate during the 



equinoxes. 



* * * * * * * * * 



Archelaus, who lived in the year 448, 13. C, was the last 

 philosopher of the Ionian Sect; ho said, regarding the sun, — 

 " It is a star, only it surpasses in size all other stars." The con- 

 jecture for what is not based upon any measurement, or any 

 observation, deserves no other name, was certainly very bold and 

 very beautiful. Let us pass over an interval of more than two 

 thousand years, and we shall find the relation of the sun and 

 the stars established by the labors of the moderns, upon a basis 

 which defies all criticism. During nearly a century and a half, 

 astronomers endeavoured to determine the distance between the 

 stare and the earth ; the repeated failures with which their re- 

 searches were attended, seemed to prove that the problem was 

 insolvable. But what obstacles will not genius, united to per- 

 severance, overcome ? We have discovered within a very few 

 years the distance which separates us from the nearest stars. 

 This distance is about 206,000 times the distance of the sun 

 from the earth, more than 206,000 times 95,000,000 of miles. 

 The product of 206,000 by 95,000,000 would be too much above 

 the numbers we are in the habit of considering, to warrant its 

 annunciation. This product will still more strike the imagina- 

 tion, when I refer to the rapidity with which light travels. 

 Alpha, in the constellation of the Centaur, is the star nearest to 

 the earth, if it be allowable to apply the word near to such dis- 

 tances as those of which I am about to speak. 1 he light of 

 Alpha, of the Centaur, takes more than three years to reach us, 

 so that were the star annihilated, we should still see it for three 

 rears after its destruction. Recall to your recollection that light 

 "travels at the rate of 192,000 miles in a second; that the day is 

 composed of 86,400 seconds, and the year of 365 days, and you 

 will feel as thunderstruck before the immensity of these numbers. 

 Furnished with these data, let us transport the sun to the place 

 of this, the nearest star, aud the vast circular disc, which in the 

 evening occupies a considerable time in descending entirely be- 

 low the same line, would have dimensions almost imperceptible, 

 even with the aid of the most powerful telescopes, and its bril- 

 liancy would range among the stars of the third magnitude, you 

 will thus see what has become of the conjecture of Archelaus. 

 One may perhaps feel humiliated by a result which reduces so 

 far our position in the material world ; but consider that man 

 has succeeded in extracting everything from his own resources, 

 ■whereby he is elevated to the highest rank in the world of 

 thought. 



We would remark that in the recent works of complete astral 

 catalogues, we shall find that the number of stars visible to the 

 naked eye in a single hemisphere, namely, the northern, is less 

 than three thousand. A certain result, and one, which, notwith- 

 standing will strike with astonishment, on account of its small- 

 ness, those who have only vaguely examined the sky on a beau- 

 ful winter night. The character of this astonishment will change 

 if we proceed to the telescopic stars. Carrying the enumeration 

 to the stars of the fourteenth magnitude, the last are seen by our 

 powerful telescopes, we shall find by an estimate which will 

 furnish us the minor limit, a number superior to 40,000,000, 

 (40,000,000 of suns I !) and the distance from the farthest of 

 them is such that the light would take from three to four thou- 

 sand years to traverse it We are then, fully authorized to say, 

 that the luminous rays, — those rapid couriers, — bring us, if I 

 may so express it, the very ancient history of these distant 

 worlds. A photometric experiment, of which the first indications 

 exist in the Cosmo.theoros of Huygens, an experiment resumed 

 by Wollaston a short time before his death, teaches us that 

 20 000 of stars the same size as Sirius, the most brilliant of the 



firmament, would need to be agglomerated to shed upon our 

 globe a light equal to that of the sun. On reflecting upon the 

 well known fact, that some of the double stars, are of very differ- 

 ent and dissimilar colours, our thoughts naturally turn to the 

 inhabitants of the obscure aud revolving planetary bodies which 

 apparently circulate around these suns ; and we would remark, 

 not without real anxiety for the works, the paintings, of the 

 artists of these distant worlds, that a day lightened by a red 

 light, succeeds not a night but a day, equally brilliant, but illu- 

 minated only by a green light. 



But abandoning these speculations, however worthy they may 

 be of admiration, we shall come back to the chief question, which 

 I have proposed to treat in this account, to try, if possible, to 

 establish a connection between the physical nature of the sun and 

 of the stars. We have succeeded by the help of the polarizing 

 telescope, in determining the nature of the substance which com- 

 poses the solar photosphere, because by reason of the great appa- 

 rent diameter of the orb, we have been able to observe separately 

 the different points of its circumference. If the sun were removed 

 from us to a distance where its diameter would appear as small 

 to us as that of the stars, this method would be inapplicable, the 

 colored rays proceeding from the different points of the circum- 

 ference would then be intimately mixed, and, we have said 

 already, their mixture would be white. It appears, then, that 

 we must not apply to stars of imperceptible dimensions, the pro- 

 cess which so satisfactorily conducted us to the result in regard 

 to the sun. There, are, however, some of these stars, which 

 supply us with the means of investigation. I allude to the 

 changing stars. Astronomers have remarked some stars whose 

 brilliancy varies considerably; there are even some which, in 

 a very few hours, pass from the second to the fourth magnitude ; 

 and there are others in which the changes in intensity are much 

 more decided. These stars, quite visible at certain epochs, totally 

 disappear, to reappear in periods longer, or shorter, and subject to 

 slight irregularities. Two explanations of these curious phenome- 

 na present themselves to the mind ; the one consists in supposing 

 that the star is not equally luminous on all parts of its surface, 

 and that it experiences a rotatory movement upon itself; thus it 

 is brilliant when the luminous part is turned towards us, and dark 

 when the obscure portion arrives at the same point. According 

 to the other hypothesis, an opaque, and, in itself non-luminous 

 satellite, circulates round the star, and eclipses it periodically. In 

 accordance with one or the other of these suppositions, the light 

 which is exhibited some time before the disappearance, or before 

 the reappearance of the star has not issued from all points of the 

 circumference. Hence, there can be no doubt of the complete 

 neutralization of the tints of which we have just spjoken. 



If a changing star, when examined by a polarizing telescope 

 remains perfectly white in all its phases, we may rest assured that 

 its light emanates from a substance similar to our clouds, or our 

 inflamed gas. Now, such is the result of the few observations 

 that have been hitherto made, and which will be highly useful 

 to complete. This means of investigation demands more care, 

 but succeeds equal!}' well, when applied to those stars which ex- 

 perience only a partial variation in their brilliancy. The con- 

 clusion to which these observations conduct us, and which we 

 may, I think, witnout scruple generalize, may be announced in 

 these terms; our sun is a star, and its physical constitution is 

 identical with that of the millions of stars with which the firma- 

 ment is strewed. — American Annual of Scientific Discovery. 



Mode of Constructing Telegraphs in India. 



From Calcutta to Rajraoole, the conductor is laid under ground, 

 in a cement of melted resin and sand. From that village through 



