June 1, 1870.] 



HARWDICKE'S SCIENCE- GOSSIP. 



121 



MARINE AQUARIUM. 



N order to assist 

 those who are 

 willing to pos- 

 sess a cheap ma- 

 rine aquarium, 

 ^and to cultivate 

 the study of ma- 

 rine zoology by 

 its means, I purpose to relate 

 my experiences. They com- 

 mence from the year 1867, 

 when I kept an anemone 

 {Actinia Ilesembryanthemitm) 

 in a small shallow porcelain 

 vessel partially filled with sea- 

 water, for some length'of time. 

 My next step was to buy a 

 fresh supply of sea-water, as 

 also a small dessert-dish of 

 about eight inches in length, 

 six inches iu breadth, aud two 

 inches in height ; aud to this the anemone was 

 transferred, together with a piece of the seaweed 

 (Cladophora arcta). An improvement was now sug- 

 gested to me, viz., that of syringing the water, 

 which improvement I immediately adopted, and 

 syringed it daily by means of a small glass syringe. 

 Shortly afterwards I noticed a quantity of very 

 young sandhoppers crawling about among the tufts 

 of the Cladophora, which I immediately removed 

 and conveyed to a separate receptacle. The sand- 

 hoppers were fed occasionally with small fragments 

 of meat, of which they seemed very fond, and 

 ultimately grew to a fine size, some of them to 

 nearly an inch in length. 



In the year 1868 I obtained a glazed earthenware 

 baking-dish of nearly two feet in length, sixteen 

 inches in breadth, aud three inches in height, and 

 capable of holding nearly a gallon of water. To 

 this I transferred my live stock, and now took a 

 trip to the sea-side, from whence I obtained a few 

 more anemones, as also a limpet, which very soon 

 attached itself to the sides of my dish, and made 

 itself quite at home. 

 No. 66. 



Some wooden wedges were procured and pushed 

 underneath the dish, giving to it an inclination, and 

 by this means the water became deeper gradually ; 

 the anemones chose their depths. 



The limpet very often crawled so far above the 

 water-mark that it was left quite dry, in which 

 state it was inactive, but immediately became quite 

 lively when a stream of sea-water from the syringe 

 was made to play upon it. There was a consider- 

 able amount of syringing required to keep this 

 aquarium in good order. One or two mussels were 

 now introduced, and fastened themselves by means 

 of their byssus, and seemed to thrive very well, 

 when, from some slight cause or other, one of them 

 died ; the rest immediately followed. The water 

 consequently became thick and turbid, and had a 

 very peculiar odour. The few stones which I had 

 introduced became of an inky colour, and when 

 syringed the water gave out an odour of sulphu- 

 retted hydrogen. The remedial process was the fol- 

 lowing : — Everything had to be taken out in the first 

 place ; in the second place the dish was placed for a 

 couple of hours in the open air, after which time 

 the odour disappeared. 



I kept this aquarium in good order for six months 

 in the year 1868, out of which six the limpet lived 

 for two months. 



In June 1868 I bought a propagating-glass of a 

 foot in diameter and a foot in depth, capable of 

 holding two gallons of water. A piece of slate was 

 cut into a circular form and placed therein at an 

 angle of forty-five degrees, making an inclined 

 plane, upon which stones, etc., could be arranged. 

 The light from the front of the aquarium was 

 stopped off by thick dark paper, so that only dia- 

 gonal rays of light entered it. The object of this 

 proceeding was to prevent that excessive growth of 

 conferva? which is so annoying, and to keep the 

 water at the back of the slate cool and dark. The 

 room in which this aquarium stood was much ex- 

 posed to the heat of the sun, and I remember one 

 afternoon looking at the thermometer and finding 

 that it registered ninety degrees Eahrenheit. The 

 method of aeration was as follows :— Firstly, a large 



G 



