Dr. E. L. Moss. Observations on Arctic Sea-water and, Ice. 551 



subglacial surface of the salt ice of our watering berg to study its 

 characters en masse. Similar dust, but in microscopic quantity, was 

 procured from a line 2 feet deep in a heavy floe, a mile in diameter and 

 two from the shore, drifted into a curve of the coast south of Cape 

 Joseph Henry, and at the same depth from an old " blue top " in Black 

 Cliffs Bay, and also from the dust-line already mentioned as containing 

 the saxifrage leaf at a depth of 45 feet. 



A very much worn floe to seaward of the ship supplied a large 

 quantity of dust with precisely similar inorganic contents, but enor- 

 mously magnified in apparent quantity and converted into a slimy, 

 granular, sour-smelling mud by a growth of a phycochromaceous Alga.* 

 Some of the granules deep in ice were altogether inorganic, others 

 held another Alga composed of groups of dark brown spheres ^ inch 

 in diameter, associated with spined hemispherical caps 1 J 00 inch 

 diameter, apparently the skins of zygospores. In dust-spots under- 

 lying distinctly salt ice Diatomacece naturally attached f were not 

 uncommon. 



The inorganic part of the dust consists of a reddish impalpable 

 sand of even- sized particles, rarely reaching T wo inch in diameter, but 

 averaging one-tenth of that size. Placed in a Sonstadt's solution, 

 specific gravity 2*72, it separates into a red part that floats, and a 

 much smaller dark green part that sinks. The former consists of 

 angular and rounded transparent quartz and rounded red quartz. 

 The fraction that sinks contains rounded grains of hornblende, angular 

 and rounded augite, brown scales of mica, and numerous crystals of 

 magnetite, sharply angular and often imbedded in augite or quartz. 



The dust becomes bright red on incineration, but some of the par- 

 ticles still remain magnetic. I searched carefully for, but never found, 

 a magnetic particle capable of reducing sulphate of copper. 



Two samples of ice-dust were obtained from icebergs, the one at Cape 

 Frazer, the other at Cape Louis Napoleon. In both instances the dust 

 was in granules imbedded 20 feet or more from the top surface of the 

 berg. Neither contained any organic matter. One remained on the 

 filter-paper aggregated in the granules or oolite-like grains. Both 

 effervesced with hydrochloric acid, but otherwise possessed the same 

 mineral characters as the floeberg dust. 



During winter at Floeberg Beach an attempt was made to collect 

 atmospheric dust by means of an extemporised Maddox aereoscope, 

 but it invariably got blocked with snow when there was any wind, and 

 was of course useless when there was none. A sheet of glass, exposed 

 in absolutely calm weather on top of Thermometer Hill, was more suc- 

 cessful. When the minute prisms of ice constantly falling (even in 

 an atmosphere so clear that our astronomer made successful observa- 



* Identified by Professor Dickie as Nostoc aureum. 



f Identified by Rev. Eugene O'Meara as Fragillaria oceanica. 



