NARRATIVE OF THE CRUISE. 7 



close to the window this effect was not felt, because the reflectors could be exposed 

 directly to a wide range of illuminated sky, and did not cease to gather light from some 

 part of it, unless the motion were very extreme indeed. The oblong table had its feet 

 securely screwed to the deck, and the simple oval-topped wooden stools occupied by the 

 microscopists were also screwed to the deck on each side of the window. They were so 

 placed, and of such a height, that the sitter, by jamming his knees against the 

 frame of the securely fixed table, could hold himself firm and motionless. The micro- 

 scopes were secured to the table at will in any position by means of small brass holdfasts. 

 With all these arrangements for steadiness it was found possible during a gale of 

 wind, provided that the port had not to be closed altogether, to work comfortably, even 

 with very high powers. A No. 10 immersion of Hartnack was used successfully under 

 such circumstances with a drawn-out tube. 



Fig. 3.— The Holdfast. 



The holdfast is a simple instrument (fig. 3), well known to artificers of all kinds, but 

 it was found so useful as a means of clamping microscopes on board ship, that it is as 

 well to give some description of it here. It consisted of a piece of stout brass rod, about 

 4 inches long and ^ of an inch in diameter, to which was fixed at right angles by one of 

 its ends a stout flat strip of brass, about ^ an inch broad. This strip is slightly bent 

 downwards and again upwards a little at its free tip, as seen in the woodcut. A neat 

 vertical hole, large enough to receive the rod freely, is bored in the table where the 

 microscope is to be used. When the free end of the horizontal arm is placed upon 

 any part of the foot of the microscope, a slight pressure on the rod downwards into 

 the hole clamps it firmly in any position in which it may stand. A slight pull on the 

 rod frees it instantly, and the microscope can thus be secured in any position round the 

 hole with the greatest ease. There is no other method by which this can be effected 

 so readily, and in working at sea, unless the instrument be thus fixed, it is often liable 

 to be upset or thrown altogether off the table at any moment. Microscope lamps with 

 ring feet may be conveniently secured to the table in the same manner. 



The spirit in constant use for the preservation of specimens was stowed in one of the 

 ship's powder magazines, specially retained for the purpose. From this store a tank 



