12 



decay is very evident ; but what can make it 

 sink?" 



He replied, by shewing us several little shell- 

 fish adhering to the under side of a bit of weed. 

 "These," said he, "must have been deposited 

 there before it was torn from its native rocks by 

 the current ; in the course of their long voyage 

 they grow ; and their increased size and weight 

 gradually sink the weed. My attention was first 

 turned to this curious circumstance from having 

 observed some of the weed lying edgewise in the 

 water ; I had it taken up, and found some heavy 

 limpets attached to the lower edge." 



Mrs. P acknowledged this was quite a 



new fact to her. 



20th. The captain amused us to-day by 

 shewing a very simple method of ascertaining 

 the saltness of the sea, which any person can 

 try. He dried a towel in the sun, weighed it 

 carefully, and I noted its weight. It was then 

 dipped in sea water, and being wrung sufficiently 

 to prevent it from dripping, it was again weighed, 

 the increase of weight being that of the water 

 imbibed by the cloth. It was now thoroughly 

 dried, and once more weighed, and the excess of 

 this weight, above the original weight of the 

 cloth, shows the quantity of the salt retained by 

 it; then, by comparing the weight of this salt 

 with that of the sea-water imbibed by the cloth, 



