112 Voyage of the Novara. 



On the 27th June, at midday, we had arrived in 27** 2' N. 

 Lat., and 24." 7' ^- L,ong., and lay in a perfect calm, the 

 mirror-like aspect of the sea allowing us to take a deep-sea 

 sounding with what is called Brooke's apparatus. This consists 

 of a tuhe, which runs through a thirty-pound shot, fastened to 

 a thin line. As the shot, however, cannot easily be drawn up 

 after the sounding, there is an ingenious mechanism, by means 

 of which, on touching the ground, it is detached from the tube, 

 which may then be drawn up, the shot remaining in the sea. 

 The tube has a funnel-shaped opening at its lower extremity, 

 by which a portion of the ground may likewise be brought up 

 for scientific examination. 



In the afternoon a boat provided with everything requisite 

 for the sounding, was launched, and the operation began. Un- 

 fortunately there were only 4050 fathoms of line, as we did not 

 find at Gibraltar the quality required for the purpose. The 

 whole stock ran entirely out without reaching ground ; we 

 could therefore do nothing more than make the attempt to 

 heave the tube without the shot. In this, however, we suc- 

 ceeded only in so far as regarded the first 2000 fathoms ; then 

 the line broke, and the remainder was lost. One of the 

 causes of this accident was the sudden rise of the trade- 

 wind which increased so much as to engross nearly our entire 

 attention. 



To convey an idea of the time a ball of this kind takes to 

 descend through the difierent strata of water, which increases 

 in density in proportion to the depth attained, we annex the 



