XIV 
THE VOYAGE OF H.M.S. CHALLENGER. 
meiitd ; before we meet with similar definite statements on deep-sea soundings centuries 
pass awa}'. Plutarch * says : — “The geometers think that no mountain exceeds 10 stadia 
(60G7 feet) in height, and no sea 10 stadia in depth.” Cleomedes’^ says: — “Those who 
doubt the sphericity of the earth on account of the hollows of the sea and the elevation 
of the mountains are mistaken. There does not in fact exist a mountain higher than 
15 stadia (9107 feet), and that is also the depth of the ocean.” 
The documents of the i\Iiddle Ages relative to orography and bathymetry are 
indefinite and unimportant. The wide-spread opinion among sailors, that the greatest 
depth of the sea is found near the steepest coasts, appears to be very ancient, and is 
partly founded on fact. Ibn Khaldoun, who, in the fourteenth century, wrote his famous 
history of the Berbers, remarks that if the highest mountains are situated near the sea, it 
must be n'garded as a providential arrangement to arrest the invasion of the ocean.® 
Nicolaus Cusanus, who lived in the first half of the fifteenth century, invented an 
apj>aratus consisting of a hollow sphere, to which a weight was attached by means of a 
hook, intended to carry the sphere down through the water with a certain degree of 
velocity. On touching the ground the hook became detached, the weight remained 
at the bottom, the sphere ascended alone, and the depth was calculated by the time it 
took to return to the surface."* This apparatus was afterwards improved by Piichler, 
Allx;rti,‘ and Hooke,® but the various instruments produced were not satisfaetory as 
regards sounding in the deep sea. 
Science, and in a special manner what may be called the Science of the Globe, plays 
a large part in the intellectual and moral changes whieh characterise the transitional 
period known as the Renakssance. The thirty years from 1492 to 1522, through the 
discoveries of Columbus, Vasco di Gama, and Magellan, added a hemisphere to the 
chart of the world. Not only did these voyages double at a single bound all that 
wa.s previously known of the surface of the earth, but by creating new ideas, enlarging 
the field of research, observations, and studies, they contributed more than anything 
else to the progress of the past four hundred years, and the rapid development of 
imKlern civili.sation. The existence of the Antipodes, and the sphericity of the earth, 
were no longer scientific theories, but practically demonstrated facts ; the fundamental 
principles of all scientific geograj>hy were for ever established. 
During his voyage across the Pacific, l\lagellan^ attempted, for the first time, to 
sound in the open ocean. Navigators at that time had sounding lines of only 100 and 
200 fathoms in length. With these Magellan did not reach bottom between the coral 
i.slnnds of St. I’aul’s and Bos Tiburones, and he somewhat naively concluded that this was 
* townnls the end of the first century a.d. 
’ n<iurishe<l prolwhly in the second centurj’ a.d. 
* Ihn Kbnidoun, Ilistoire dcs I/erlKjrs, trad, de I’Amhe par M. le Slanc, torn. i. p. 194, Paris, 1852. 
* For dt-j-riplion of thU apparatus sec Po;y?cn4orf, Gescliichte der Phyaik, p. IIG, Leipzig, 1879. 
* I K4-1 172 A.D. • 1635-1703 A.D. M470-1521 A.D. 
