54 ALLMAN. — USE OF THE TOWING NET. 



The cliief difficulty which the collector will here have to contend 

 against will be found in the presence of floating refuse matter 

 which is being constantly discharged from the ship, and which 

 when the vessel is under way is generally carried clear of the net 

 by the force of the water thrown off from the ship's sides. In 

 order to avoid as much as possible this source of annoyance, the 

 towing line may be attached to the extremity of a long pole fixed 

 at right angles to the side of the ship. 



Freeing the Net of its Contents. 



The ordinary towing net immediately on being hauled on board 

 is to be carefully turned inside out into a vessel containing some 

 sea-water in which it is to be moved about in order to wash off 

 such minute organisms as may be adhering to its surface. The 

 kind of vessel best suited for this purpose will be found to be 

 a white glazed earthenware pan provided with a lip, such as are 

 used in dairies for holding milk. 



From the washings of the net the larger objects are now to 

 be removed, and quickly transferred to clear glass jars of sea- 

 water for further examination ; while the water with the remain- 

 ing organisms should be poured from the pan into one or more 

 such jars, each capable of holding about half a pint. 



These smaller organisms are fi-equently so colourless and trans- 

 parent that it is at first difficult to see them in the jars ; a little 

 practice, however, will enable the observer to recognise them, 

 and he must now transfer to other jars, containing sea- water, 

 such as he wishes to keep and observe further in a living state, 

 for if left crowded together, even for a few hours, the water will 

 become vitiated, and the delicate, frequently gelatinous organisms 

 become decomposed and worthless for observation. * 



This separation and transference is best effected by glass dip 

 tubes. 



Results obtained. 



The objects captured in the towing net are very numerous and 

 various, and are among the most beautiful and interesting of 

 the more simply organised inhabitants of the sea. The towing 

 net has been hitherto used almost exclusively in the temperate and 

 equatorial latitudes, and we, as yet, know very little of what may 

 be obtained by it in the Arctic Seas. The following account of 

 its results applies, therefore, directly only to those seas where the 

 naturalist has used it, but it will nevertheless serve as a guide 

 to the Arctic explorer, and suggest to him what he ought to 

 keep in view. 



Plants. 



The members of the vegetable kingdom which will find their 

 way into the towing net will chiefly consist of the very low groups 

 constituting the orders DiatomacecB and Oscillator ice ^ the former 

 provided with siliceous cases and retaining indefinitely their external 

 form ; the latter destitute of any firm support, and speedily 

 decomposing and losing all their important characters. In some 



