222 THbJ SCOTTISH MARINE STATION AND ITS WORK. 



centre of tlie quarry. Slie consists of an iron hull, sixty- 

 four feet long by thirteen feet broad, formerly used as a 

 lighter ; about the centre of her length a raised cabin was 

 built, leaving a free space at either end, and thus imparting 

 to the whole a striking resemblance to the craft of the toy- 

 shops after which she is named. The cabin is divided into two 

 compartments, one of which is furnished with arrangements 

 for physical work, and with appliances for keeping speci- 

 mens alive in vessels through which a constant stream is 

 passed, a wind-pump on the roof raising the water for this 

 purpose. The other room contained tables for microscopic 

 woi'k, shelves for reagents, and the usual paraphernalia of a 

 biological laboratory. The quarry itself was made to serve 

 as a kind of natural aquarium by enclosing specimens of 

 various kinds in submerged cages, which were attached 

 either to the " Ark " itself or to suitable floats in various 

 places. 



The " Medusa,^' the steam yacht used for sounding and 

 dredging, is fifty-one feet in length, twelve feet in beam, 

 and a little over thirty tons burthen, yacht measurement. 

 There is a single mast in the fore part of the vessel, and 

 from it there projects forwards a derrick with blocks through 

 which pass the sounding or dredging lines. Each of these 

 has its own special drum, placed on an axle abaft the mast, 

 and actuated by a small steam engine. In the after part of 

 the vessel is a cabin, capable of holding several persons, in 

 which it is possible to examine the captui-ed material with 

 the microscope. 



The sounding line is of hemp, this being regarded as safer 

 where instruments are attached, while the depths are so 

 small that but little saving in time would be effected by the 

 use of wire. The dredging rope is of phosphor bronze, 

 nearly half an inch in diameter, and 200 fathoms of it are 

 coiled round the drum. 



Since the station was inaugurated several changes in its 

 arrangements have taken place. A spacious laboratory with 

 aquaria in the basement has been erected on shore at Granton 

 within a large enclcsure, and the " Ark " has been removed 

 to Millport in the Firth of Clyde, where it serves as a kind 



