HYDROGRAPHICAL SURVEY. 177 



was derived from the nature of the bottom of the 

 sea. But on observing that the water was very im- 

 perfectly transparent, insomuch, that to7igues of 

 ice, two or three fathoms under water, could scarce- 

 ly be discerned, and were sometimes invisible, and 

 that the ice floating in the olive-gi*een sea was of- 

 ten marked about the edges with an orange-yellow 

 stain, I was convinced, that it must be occasioned 

 by some yellow substance held in suspension by the 

 water, capable of discolouring the ice, and of so com- 

 bining with the natural blue of the sea, as to pro- 

 duce the peculiar tinge observed. 



For the purpose of ascertaining the nature of the 

 colouring substance, and submitting it to a future 

 analysis, I procured a quantity of snow from a piece 

 of ice that had been washed by the sea, and was 

 greatly discoloured by the deposition of some pecu- 

 liar substance upon it. A little of this snow, dis- 

 solved in a wine glass, appeared perfectly nebulous ; 

 the water being found to contain a great number of 

 semi-transparent spherical substances, with others 

 resembling small portions of fine hair. On examin- 

 ing these substances with a compound microscope, I 

 was enabled to make the follomng observations. 



The semi-transparent globules appeared to consist 

 of an animal of the medusa kind. It was from l-20th 

 to l-30th of an inch in diameter. Its surface was 

 marked with twelve distinct patches or nebulae, of 

 dots of a brownish colour ; these dots were disposed 



VOL. I. M 



