Vol. XXIl. No. 5.] 



POPULAE SCIENCE KEWS. 



75 



The cancerous particle produced only local inflam- 

 mation of short duration. The lecturer maintained 

 cancer to be contagious, and the disease-germ to be 

 smaller than the lung-capillaries; but as yet the 

 nature of the germ is unknown. 



The minister of war is trying to relieve the cui- 

 rassiers of the burden of their cuirasses. The cui- 

 rassier is commonly severely injured by a fall from 

 his horse, neck or ribs being especially liable to frac- 

 ture. Even in the exercises in time of peace, the 

 accident is not unknown. The difficulty of mount- 

 ing is also to be considered. But the chief argu- 

 ment is, that the cuirass is no defence against the 

 projectiles of modern warfare, but increases, rather, 

 the severity of the wounds received. Conclusive 

 proof of this was easily obtained by filling a cuirass 

 with animal flesh, and making it the target for a few 

 rifle bullets. Not only was it readily pierced, but 

 pieces of the metal were driven into the substance 

 of the flesh, adding to the severity of the wounds. 



Photography is gaining increasing importance 

 in the criminal courts. With its help a Berlin 

 merchant was lately convicted of crooked ways in 

 keeping his accounts. The slightest differences in 

 color and shade of inks are made manifest in the 

 photographic copy : blue inks appear nearly white ; 

 brown inks, on the contrary, almost black. The 

 books of the accused were submitted to a photog- 

 rapher, who took off the pages concerned, and 

 brought into court the most undoubted ocular 

 proofs of the illegitimate after-entry of some of the 

 accounts. A subsequent chemical test substanti- 

 ated this evidence. The photographic is to be pre- 

 ferred to the chemical test, because it brings its 

 proofs into the court, and submits them to inspec- 

 tion, at the same time leaving the document under 

 examination unharmed; while the results of a 

 chemical test must be taken on the evidence of the 

 chemist alone, and the writing examined is per- 

 haps destroyed. In another case similar to the 

 above the changing of the date of a note by an 

 insignificant erasure and addition was proved by 

 means of photography. 



The scientific and technical societies of Berlin 

 are about to build a house for their common use. 

 Three connected lots in the best quarter of the city 

 have been secured, and a stock company formed, 

 with the expectation that members of the interested 

 societies will take the stock, of which 2,200,00(| 

 marks will bo issued. The building will contain 

 business and reading rooms to be rented to the 

 several societies, and common assembly rooms. 

 The control of the building will be in the hands of 

 those renting its rooms, and thus the ends and aims 

 of the enterprise confined strictly to purposes of 

 science. Already different medical, chemical, 

 polytechnical, electro-technical, geological, geo- 

 graphical, and anthropological societies have signi- 

 fied their approval of the plan, and a committee 

 has been formed of leading scientists and physi- 

 cians to direct the movement. 



The Government is about to erect here a build- 

 ing for the execution of colossal statues and monu- 

 ments. The estimated cost is thirty -eight thousand 

 marks, which sum has already been appropriated. 



At the Vienna International Balloon Exhibition, 

 which is to be opened on the 1st of April, the 

 German Society for the Promotion of Ballooning 

 will be appropriately represented. Among other 

 models of interest will be exhibited numerous ap- 

 pliances for aerial locomotion. In the course of 

 the summer a series of ascensions for purely 

 scientific purposes will be made. The buildings 



for the exposition are already completed, and the 

 management is in the hands of a committee con- 

 sisting of the landgrave FUrstenberg, Max Prince 

 Furstenberg, Alexander Prince Salms, and others. 



An interesting essay on the prime meridian was 

 recently sent to the French Academy of Sciences 

 by Alexis von Tillo. As is well known, there is as 

 yet no common meridian agreed upon by the dif- 

 ferent nations for the reckoning of longitude; Eng- 

 land using the riieridian of Greenwich, France that 

 of Paris, Germany that of Ferro, and the United 

 States that of Washington. By a series of computa- 

 tions, which need not be here described. Von Tillo 

 found the co ordinates of the orographic centres of 

 gravity of the four continents. These centres form 

 a tolerably regular quadrangle, the longest side 

 being that connecting the centres of Asia and 

 North America. It is ninety-two degrees long, and 

 lies between the parallels 43 and 45 north latitude 

 The line connecting the centres of Africa and South 

 'America is eighty-two degrees in length, lying 

 between the tropics. The geometrical centre of this 

 quadrangle lies near the Azores and Canary Islands ; 

 and as the meridian of Ferro cuts this region, the 

 writer claims this as the natural prime meridian of 

 the earth. 

 Berlin, Fe6. 24, 1888. 



[Orl^Dal In Popular Science A>w«.] 

 HOW BIRDS LEAKN TO SING. 



BY SAMUEL liRAZIKR. 



Most people probably imagine that birds sing 

 by instinct ; that the song of the robin is as natu- 

 ral to him as his red breast ; that the bluebird is 

 not more liable to change its note than its color ; 

 and that, untaught, the nightingale will always 

 sing the same beautiful song. 



This common impression, however, is erroneous. 

 Young birds will never sing the song peculiar to 

 their tribe if they have never heard it, but if 

 associated with some other bird, will learn its song 

 instead. A redstart once built its nest under the 

 eaves of a house where a caged chaffinch hung in 

 a window underneath. The redstart learned the 

 chaffinch's song. Another redstart was noticed to 

 repeat the notes of a blackcap which had its nest 

 close by. 



The whinchat and wheatear have naturally but 

 little variety of notes, but will become much better 

 songsters if confined with other birds; and the 

 bullfinch can be taught to whistle complete tunes, 

 although its own natural notes are harsh and insig- 

 nificant. On the other hand, the nightingale in 

 confinement will sometimes exchange its own 

 beautiful song for that of some other bird that it 

 may hear. The Hon. Daines Barrington says that 

 he saw a linnet which had been taken from the 

 nest when only two or three days old, and which, 

 not having any other sounds to imitate, almost 

 learned to articulate, and could repeat the words 

 " pretty boy " and some other short sentences. He 

 educated nestling linnets under the three best-sing- 

 ing larks, — the skylark, woodlark, and titlark, — 

 every one of which, instead of the linnet's song, 

 adhered entirely to that of their respective instruct- 

 ors. When the note of the titlark was thoroughly 

 fixed, he hung the linnet which had learned it in 

 a room for three months with two common linnets 

 which were in full song. The educated linnet, 

 however, never borrowed any passage from the 

 other linnets, but adhered steadfastly to that of 

 the titlark which it had learned. At Knighton, in 

 Radnorshire, he saw a goldfinch which sang exactly 

 like a wren, and uttered no proper note of its 

 species. This bird had been taken from the nest 

 when it was only two days old, and was hung in a 



window opposite a small garden, where it had, no 

 doubt, heard and learned the wren's song, having 

 never had the opportunity to learn that of the gold- 

 finch. Birds taken from the nest two or three 

 weeks old have already learned the call-notes of 

 their species. These and many similar facts go to 

 prove that birds do not sing by instinct. They 

 learn their songs from their parents. If they have 

 no opportunity of hearing the song peculiar to their 

 species, they never sing it, but will learn any other 

 instead ; Just as an American child taken to France 

 when a few weeks old, would never speak Eng- 

 lish if he never heard it, but would learn to speak 



French. 



— • — 



[Specially reported for the Popular Science ^ew9 from the 

 Observatory of the College of New Jersey.] 



ASTRONOMICAL PHENOMENA FOR MAY, 



1888. 



The Planets. — Mercury passes superior conjunc- 

 tion with the Sun on May 10, and becomes an 

 evening star. At the end of the month it sets 

 about an hour and a half after sunset, and may be 

 seen in the twilight. Venus is still a morning star, 

 but is approaching the Sun, and is not in very good 

 position for observation. Mars is still in good posi- 

 tion for observation, but is increasing its distance 

 from the Earth, and growing fainter. It is on the 

 meridian at about 10 p.m. on May 1, and at about 

 8 P.M. on May 31. It moves slowly westward 

 until May 21, when it begins to move eastward 

 among the stars. It is west and north of the first- 

 magnitude star Spica {Alpha Virginis). Jupiter 

 is in the constellation Scorpius, moving slowly 

 westward. It is near the second-magnitude star 

 Beta Scorpii, passing it on May 20 at a distance 

 of only 2'. At this time the star will be too 

 near the planet to be seen with the naked eye. 

 The planet is on the meridian about lA. 30m. am. 

 on May 1, and at about l\h. 20m. on May 31. It 

 is in opposition with the Sun on May 21. 



For the benefit of owners of small telescopes I 

 give a list of the eclipses of Jupiter's satellites 

 which are visible in the United States during the 

 month. Before opposition, only the disappearances 

 can be seen, the reappearances occurring while the 

 satellite is behind the planet. After opposition, 

 only the reappearances are seen, for a similar 

 reason. As seen in an inverting telescope, the dis- 

 appearances take place on the upper left-hand 

 quadrant, and the reappearances on the upper right- 

 hand quadrant, very close to the limb, as the 

 shadow at opposition is directly behind the planet. 

 The satellites are designated as I., II., III., and IV , 

 in the order of increasing distance from the planet. 

 The times given are Eastern standard time. 



Keappeabances. 



Disappearances. 



II. — May 2, 



I. — May 6, 



I. — May 7, 



It. — May 12, 



III. — May 13, 



I. — May 15, 



II. — May 19, 



III. — May 21, 



5b. 26m. A.M. 



5b. 2m. A.H. 

 llh. 31m. p.m. 



9h. 19m. P.M. 

 lOh. 2Jm. P.M. 



lb. 25m. A.M. 

 llh. 64m. P.M. 



2b. 22m. A.M. 



I. - May 23, 

 II. — May 27, 

 I. — May 31, 



llh. 55ra. P.M. 

 4h. 54m. A.M. 

 lb. 49m. A.M. 



With small telescopes the satellites also disappear 

 when they are between the Earth and Jupiter. 



Saturn is still in the western sky in the evening, 

 setting before midnight. It is in the constellation 

 Cancer, and forms a large triangle with Beta Gemi- 

 norum and Alpha Canis Minoris. Uranus is in 

 Virgo, about 8° north and west of Spica (Alpha 

 Virginis). On May 5 it is south of Mars at a 

 distance a little greater than the moon's diameter. 

 Neptune is in conjunction with the Sun on May 19. 



The Constellations. — The positions given hold 

 good for latitudes differing not many degrees from 

 40° north, and for 10 p.m. on May 1, 9 p.m. on May 

 16, and 8 p.m. on May 31. Canes Venatici is in the 



