68 SELECTED ESS A YS FROM LA Y SERMONS 



multitudes, literally more numerous than the sands of the 

 sea-shore, over a large extejit of that part of the earth's 

 surface which is covered by the ocean. 



The history of the discovery of these living GlobigerincB , 

 and of the part which they play in rock building, is singular 

 enough. It is a discovery w^hich, like others of no less scien- 

 tific importance, has arisen, incidentally, out of work devoted 

 to very different and exceedingly practical interests. When 

 men first took to the sea, they speedily learned to look out 

 for shoals and rocks; and the more the burthen of their ships 

 increased, the more imperatively necessary it became for 

 sailors to ascertain with precision .the depth of the waters 

 they traversed. Out of this necessity grew the use of the 

 lead and sounding line; and, ultimately, marine-surveying, 

 which is the recording of the form of coasts and of the depth 

 of the sea, as ascertained by the sounding lead, upon charts. 



At the same time, it became desirable to ascertain and to 

 indicate the nature of the sea-bottom, since this circumstance 

 greatly affects its goodness as holding ground for anchors. 

 Some ingenious tar, whose name deserves a better fate than 

 the oblivion into which it has fallen, attained this object by 

 "arming" the bottom of the lead with a lump of grease, to 

 which more or less of the sand or mud, or broken shells, as 

 the case might be, adhered, and was brought to the surface. 

 But, however well adapted such an apparatus might be for 

 rough nautical purposes, scientific accuracy could not be 

 expected from the armed lead, and to remedy its defects 

 (especially when applied to sounding in great depths) Lieut. 

 Brooke, of the American Navy, some years ago invented a 

 most ingenious machine, by which a considerable portion of 

 the superficial layer of the sea-bottom can be scooped out 

 and brought up from any depth to which the lead descends. 

 In 1853, Lieut. Brooke obtained mud from the bottom of 



