514 



NATURE 



\_March 31, 1 88 1 



i 





m. 



Just these tones, hvA four octaves lower .' 



"At once it will be incredulously replied, 'No human 

 ear ever has heard, or ever can hear, tones at such a 

 depth.' I arrived at my conclusions both theoretically 

 and practically, and the two results coincided exactly." 

 For the explanation of this, those interested will do well 

 to consult the article itself. It may be noted here, how- 

 ever, that notes 3 and 4 were heard everywhere ; that the 

 Jth and 6th were perfectly distinct, but of far less power ; 

 that the 7th (the interval of the tenth) was of a power 

 and clearness entirely out of proportion to the harmonics 

 as usually heard in the organ, &c. ; and that the 8th, 9th, 

 and loth notes were only heard occasionally and with a 

 transient impression. Mr. Schuyler then points out that, 

 allowing for the fact that the diameter of Niagara is the 

 greatest possible compared with its height, the length of 

 an organ-pipe necessary to give the key-note of Niagara 

 (four octaves below note i in the diagram) would be just 

 the average height of the Falls ! The figures given are 

 170-66 feet - 10-24 feet = 160-42 feet, where the 1024 

 feet is the allowance for the extra diameter of Niagara 

 treated as an organ-pipe. 



It appears, then, that the tone of Niagara is, note for 

 note, the dominant chord of our natural scale in music. 

 Its rhythm is one note per second, with three notes in 

 each measure, the first note being the accented one, and 

 the single beats are represented by groups of three semi- 

 quavers, where M.M.6o = J, or three times three, three 

 times repeated. 



Mr. Schuyler thus concludes in words with which 1 

 heartily sympathise. " I have spoken only of the pitch 

 and rhythm of Niagara. What is the quality of its tone ? 

 Divine ! There is no other word for a tone made and 

 fashioned by the Infinite God. I repeat, there is no roar 

 at all — it is the sublimest music on earth ! " 



William Lant Carpenter 



ZOOLOGICAL RESULTS OF THE VISIT OF 

 PROF. K. MOEBIVS TO MAURITIUS' 



THIS work, which is illustrated by a map and twenty- 

 two plates, contains the results of the investigations 

 of Prof. Mobius on the marine fauna of Mauritius and 

 the Seychelle Islands, embodying the account of obser- 

 vations made by him on the spot, and of work done on 

 the collections which he brought home with him on his 

 return from his visit to the islands. It commences with 

 an account of the journey to Mauritius in 1874-75; an 

 account of the Suez Canal is given, and of the voyage 

 through the Red Sea, where Trichodesinium, the yellow- 

 ish-red floating alga: supposed by some to have given the 

 name to the sea, was met with in abundance. After the 

 well-known tanks of Aden and the Somali divers who 

 surround every ship that comes into the port have been 

 described. Reunion is touched at, and at last Mauritius. 



A concise account is given of the geographical, geo- 

 logical, and climatic peculiarities of this island, which 

 is about one-third the size of Holstein. The centre 

 of the island is occupied by a plateau elevated over 1700 

 feet above sea-level, the highest point being 2711 feet in 

 height. The plateau is surrounded on nearly all sides by 

 mountains, and from these on all sides but the northern, 



' Beitrage lur Meeresfauna der Insel Ma 

 beitet von K. Mobiui, F. Ricliter und E. 

 Otto Enslin. 1880.) 



nd der Seychellen, be 

 irtens, u.s.w. (Berlin: 



where there is a gradual inclination, rivers and streams 

 fall down very steep slopes with frequent waterfalls 

 mto the sea. Rains are very heavy, and the mountain 

 torrents swell with remarkable rapidity. The geological 

 structure of the island is entirely volcanic, with the excep- 

 tion of beds of coral rock. The' mean temperature of the 

 year is about 25-'85 C. Rain is most abundant from 

 December to May. The prevailing wind is the south- 

 east trade. Cyclones are sometimes experienced in the 

 period, December to April, but do not occur every year. 



Mauritius had originally no mammalian inhabitants 

 excepting bats. The great fruit-bat {Pteropus vulgaris) 

 is abundant in the woods. These fruit-bats are easily 

 tamed. One of them was a great pet of Mr. G. Clark, 

 now dead, who was the author of "A Brief Notice of 

 the Fauna of the Mauritius," published in the Mauritius 

 Almanac for 1859, and containing some very good obser- 

 vations. This tame bat was taken when young from its 

 mother's breast and brought up by hand. It could not 

 fly, because its wing membranes had been cut through to 

 prevent its doing so. It usually passed its time hanging 

 on to the back of a chair. Directly Mr. Clark c.ime into 

 the room it cried out loudly to be nursed. If it were not 

 taken up at once it climbed up to him, rubbed its head 

 against him, and licked his hands. If Mr. Clark sat down 

 the bat hung on at once to the back of the chair, and 

 followed all the movements of its master with its bright 

 eyes. If its master caught hold of a fruit it climbed forth- 

 with dow-n his arm to his hand to get its share, and it 

 always got two teaspoonsful out of every cup of tea or 

 coffee. If Mr. Clark took any kind of object in his hand 

 the bat climbed to it, examined it with its eyes and nose, 

 and only returned to its chair-back after completely satis- 

 fying its curiosity. It followed its master even into the 

 open air if the door was not shut to prevent its getting out. 



A good many mammals have been introduced into the 

 island, and are now abundant. A monkey from the East 

 Indies (Macacus cyui'iiwlgus) inhabits the woods, and 

 makes excursions from thence to plunder the sugar-cane 

 fields. One of the species of the curious hedgehog-like 

 insectivora of Madagascar (Centetes ecaudatus) was 

 introduced in the island at the end of the last century. 

 The animals live in damp places and lie in a state of 

 sleep (= hybernation) in the dry season, sleeping then so 

 soundly that they do not awake even when dug up. As 

 soon as the rainy season begins in November they wake 

 up and breed, producing three litters of fifteen or sixteen 

 young every year. The young follow the mother, who 

 calls them with a grunting noise, in a row behind, and 

 protects them when molested with her teeth and spines. 

 A full-grown male weighs as much as four pounds. The 

 animals are so abundant that on a moonlight night with 

 trained dogs twenty or thirty may be caught by one 

 hunter. They are eaten by the working classes. 



Besides these there is a shrew mouse, also introduced 

 from the East Indies, a small hare, and the ubiquitous 

 common rat, both of which latter gnaw and destroy the 

 su^ar-cane. A stag (Ctvjv/i- hippelaphas) introduced by 

 the Poituguese inhabits the woods. It breeds in July and 

 August, and casts its horns in December or January. 



We cannot follow the author in his short reference to 

 the birds and account of the fish. The coral-reefs of the 

 island appear to abound with animal life of all kinds. 

 Several of the corals composing them are laid dry con- 

 stantly at low tide, and remain exposed to the air without 

 injury. Go?iiastnra rctiforinis and Leptoria gracilis are 

 cited as examples of such Whilst these corals are in this 

 condition, the polyps remain entirely withdrawn, and the 

 whole surface of the coral laid bare is covered with slime, 

 which prevents its drying up. 



In the Seychelles, of which a short ac:ount is given, 

 the giant turtle {Chelonc virgata) is kept in ponds as at 

 Ascension, and is caught with a rope round the flipper, 

 and dragged out to be slaughtered when convenient. The 



