Observations on the microscopic alga which causes the discoloration of the sea in various parts of the world / by C. Collingwood.

  • Collingwood, Cuthbert, 1826-1908.
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the microscopic alga which causes the discoloration of the sea in various parts of the world / by C. Collingwood. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    1/12
    -$*4* y Observations on the Microscopic Alga tofrich causes the Discoloration of the Sea in various >arts ofjfmf World. By Dr. C. Collingwood, M.A., F.L.S. f' '■%£&! * / (Read March 11th, 1868.) Although a great deal has been written at various times on the subject of the floating substance known to sailors as sea sawdust, whale’s food, &c., it does not necessarily follow that there is not still much to be added by those who have themselves observed the phenomenon. Moreover, although travellers have from time to time recorded the appearance of this substance upon the surface of the ocean in different parts of the world, it so happens that those who have written the most elaborate articles upon it have either never seen it (as, for instance, Montagne), or had but limited opportunities for its observation, which latter was indeed the case with Ehren- berg. Again, the interesting accounts written by these naturalists have referred almost exclusively to the substance produced in the Bed Sea, and to which they attribute its name, while other observant travellers have mentioned it as a singular phenomenon of somewhat rare occurrence, giving the date, and latitude, and longitude of the event. Thus Darwin, who circumnavigated the globe, and was five years at sea, cites but two occasions on which he observed it, viz., near the Abrolhos islets, and off Cape Leeuwin ; the conferva seen near the Keeling Islands having been of quite a different character. One circumstance much dwelt on by those who have de- scribed this substance is the red colour it imparts to the sea, so much so, that whether it is De Candolle who examines the waters of the lake of Morat, or Ehrenberg at the Bay of Tor, or Montagne describing the dried specimens which had been obtained from the middle of the Bed Sea, they all agree in calling it erythrceum, or rubescens, while Ehrenberg im- proves upon this by naming De Candolle’s species Oscillatoria