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SCIENCE. 



[Vol. XX. No. 504 



eating what must be restored if fertility is to be mainlained and 

 lucrative yields obtained in the future. Such knowledge is 

 well-nigh indispensable at the present day to the grower of grain, 

 roots, and fruit if he is to compete successfully with his intelli- 

 gent neighbors. Chemistry can tell us, in a large measure, of 

 the relative fertility of a soil and point out what elements of plant- 

 food may be lacking. It is the science that makes the barren and 

 waste lands fruitful and is the chief agent in making "two blades 

 of grass grow where there was but one before." To stock-raisers 

 and dairy-farmers it lends its aid in showing the requirements of 

 animals, the daily waste of the animal organism. It ascertains 

 the composition and relative feeding-values of cattle-foods. It 

 analyzes animal products, indicating their comparative worth. 

 Chemistry stamps the value upon artificial fertilizers. 



In the by-paths of agricultiu-e, too, chemistry is of service. The 

 intelligent investigator in the important subjects of insecticides 

 and fungicides must prosecute his studies by the light of chemistry. 

 And so we might proceed, but space forbids. Let us, however, 

 remember that history emphatically shows that agriculture and 

 agricultural chemistry have progressed with equal strides, and 

 that for the future the indications are that the relationship of these 

 two will be still closer. 



If in this short sketch our claim is made good, then we perceive 

 that it is of paramount importance that agricultural chemistry 

 should form part of the education cf every boy destined for the 

 farm. Every public school in rural diftricts should teach it, not 

 merely theoretically, but practically. All the offioera of our ex- 

 periment stations should have a knowledge of its principles, since 

 no department of agriculture is independent of it. They at present 

 are not only investigators but are also the teachers of the adult 

 and practising farmer. How necessary it is then that all their 

 work should be guided by an intimate acquaintance with that 

 science which is not only the foundation of agriculture, but whose 

 laws govern its operations. 



THE REAL MOTIONS OF THE FIXED STARS. 



BT PROFESSOR A. W. WILLIAMSON, AUGUSTANA COLLEGE, BOCK IS- 

 LAND, ILL. 



It is very often stated in newspapers, and also stated in a num- 

 ber of text-books on astronomy, that 1830 Groombridge has a 

 greater velocity than the attraction of all known bodies in the 

 universe could give it. We know not how many dead suns may 

 exist, retaining their full power of attraction, though no longer 

 giving light. 



We do not, however, need this supposition to account for the 

 velocity of 1830 Groombridge. Granting the laws of gravitation 

 universal, we are able to account for any finite velocity, the at- 

 tracting bodies possessing any finite degree of brightness, by sup- 

 posing these bodies sufficiently large and distant. 



Imagine a grand central sun just as dense as ours and a quin- 

 tillion times as bright, in proportion to its surface. Suppose its 

 distance 10'- times that of our sun. Suppose its periodic time 

 10" times that of our earth. Its mass would be (10"j^ -^ (lO'"*)- 

 _ ito-'" -i- 10'°^ = 10'°" times that of our sun. Its radius would 

 be ' (/lO"" = 10^'. Its apparent surface would be (10" -=- 10^')^ 

 _ ^iQisj 2 _ ^^o"" times less than our sun. Its brightness would 

 therefore be 10— '=xl quintillion = 10-i'' or .000000000000000001 

 part of that of our sun, that is, it would be as much fainter than an 

 ordinary star as the star is fainter than the sun, invisible even by 

 the Lick telescope. 



Our system would therefore move in its orbit around this cen- 

 tral sun as many times more rapidly than the earth moves in its 

 orbit, as the diameter of the orbit is greater, divided by the num- 

 ber the periodic time is greater, that is 10" -i- 10" = 10". As our 

 earth moves over eighteen miles in a second, our system must, on 

 this supposition, move over eighteen quintillion miles in a second, 

 or about one hundred trillion times the velocity. 



It is difficult to conceive that so great a sun can have any real 

 existence, and still more difficult to imagine we are moving with 

 such velocity. It seems to me, however, not improbable that as 

 the motion of the planets in their orbits is much greater than that 



of their satellites, so the motion of the stars around the common 

 centre is far more rapid than that of the planets around our sun. 

 It seems quite likely that all are moving in the same dii-ection, 

 and that the apparent motions of those having a sensible parallax 

 are only the differences of their true motions. The sun may ap- 

 pear to be moving towards Hercules because it is moving in that 

 direction more rapidly than the average of the stars. May it not 

 also be the case that it is really moving in exactly the opposite 

 direction but more slowly than other stars ? 



LETTERS TO THE EDITOR. 



#*♦ Correspondents are requested to be as brief as possible. The writer's name 

 is in all cases required as proof of good faith. 



Chi request in advance, one hundred copies of the number containing his 

 communication loill be furnished free to any correspondent. 



The editor will he glad to publish any queries consonant loith the character 

 of the journal. 



The Ancient Libyan Alphabet. 



Professor Keane in Science, Sept. 23, having acknowledged 

 that he referred to the wrong book, should have been ingenuous 

 enough to say that, in the book he did refer to, the primary form 

 given of every letter in the Libyan alphabet is rectilinear, or a dot. 

 As he was not, I offer to place the book in the hands of the editor 

 of Science for anyone to convince himself that this is the case. 



It is a strange misapprehension of the most important point at 

 issue on the part of Professor Keane, to call the form of the letters 

 " of secondary importance." Their disputed origin can be ascer- 

 tained only by discovering their original forms. 



If Professor Keane had further been ingenuous enough to state 

 why Hanoteau likens the writing of the Touaregs to Arab and 

 Hebrew, he could not have ventured the perfectly incorrect in- 

 ference he fathers on Hanoteau, that it is " Semitic." Hanoteau 

 refers solely to his belief that the Touareg writing is always read 

 from right to left; in which opinion he was wrong, as I have 

 plenty of documents in tifinar to show. 



I shall say nothing further of Professor Keane's view of the 

 pronunciation and meaning of the word tifinar than that every 

 derivation I can find of it by French scholars regards the initial 

 t as part of the radical; which would effectually dispose of the 

 fanciful hypothesis that it comes from Phoenician. 



D. G. Brinton. 



Media, Penn., Sept. 37. 



Tvyins Among the Indians on Puget Sound. 



Twins among the Indians of Puget Sound are very uncommon; 

 but in former times, when any did appear, they had an exceed- 

 ingly hard time, as the Indians were superstitiously afraid of 

 them. During the past eighteen years, I have known of but one 

 pair among the Twana Indians, and one pair among the Clallams. 

 The Twanas were well taken care of, as the parents had always 

 lived on the reservation, where the Indian agent had previously 

 had a pair ; and so they had had an opportunity of seeing the white 

 customs in regard to them. These parents had also been educated 

 in school, and were quite civilized. To all intents and purposes 

 they were white, and so nothing was done about them except 

 that there was some talk about the former customs in regard to 

 them. 



But the pan- among the Clallams did not fare so well. Their 

 parents were old-fashioned Indians, were surrounded by old- 

 fashioned Indians, were about eighty miles from the reservation, 

 and they had never had a home on it. The home of their parents 

 was in Fort Discovery, but they were at Neah Bay, catching seals, 

 about eighty miles from home at the time the twins were born. 

 Immediately the Neah Bay Indians became afraid of them, and 

 quickly drove them and their parents away, as they were afraid 

 that the twins would scare all the fish away from their waters. 

 Accordingly, the parents returned to Port Discovery on a steamer, 

 though the Indians were quite unwilling to have them go in that 

 way, fearing that they would frighten all the fish away; and 

 earnestly wished them to walk the entire distance, over mountains 

 and through the forests or on the beach, although there was 

 neither beach or road much of the way. 



