196 



HARDWICKE'S SCIENCE-GOSSIP. 1 



Kentish Glory, otherwise called Endromis versicolor, 

 which, if it be indeed a glorious species, has ap- 

 parently ceased to honour the country whence it 

 takes its name, through the destruction of much of 

 the woodland it delighted in. The caterpillar of 

 this moth reminds us somewhat of those of 

 the Hawk-moths, being stout, and also striped. 

 When first hatched, each brood divides into two 

 or more colonies, which form a web for their 

 protection. They are then studded over with 

 minute warts or points, slightly hairy and smoke- 

 coloured. After several changes of skin, they 

 appear in full costume, being then an inch and a 

 half in length. The ground-colour is green, vary- 

 ing in hue, the stripes being white and a darker 

 green. A hump above the tail is prolonged into a 

 white horn. 



We have thus glanced slightly at the greater 

 number of our horned British caterpillars, and 

 though the transformations of most of these have 

 been watched from the egg, there are still facts 

 regarding them which have not yet been discovered, 

 since it needs long and careful observation to make 

 out the full history of a species. 



J. R. S. Clifford. 



MARINE AQUARIA. 



Sea-water.— Artificial versus Real. 



A QUARIA, and all things pertaining to them, 

 -E*~ have been so often written about of late, 

 that I should feel very reluctant to offer any re- 

 marks on the subject, had not a gentleman who 

 reads Science-Gossip (and I believe writes in it) 

 written to ask me to detail #?# experience of artificial 

 sea-water, and the management of a marine aqua- 

 rium, in the pages of that magazine. 



The first aquarium I ever set up (for I do not call 

 the different little attempts I had made when stay- 

 ing on the coast to keep some of the common 

 objects found there, for a short time in wash-hand 

 basins and] finger-glasses, aquaria) was a very 

 pretty cylindrical glass vessel, — I did not venture 

 upon a tank then, in those early days of aquarium 

 fashion, and it was supplied with clear, perfectly 

 pure s«z-water, purchased in London, sea-water 

 which was kept for the especial purpose, of proper 

 specific gravity, at an establishment near the 

 Regent's Park. 



This, my first aquarium, gave me the least 

 trouble of all in respect to the water; but it was 

 stocked for me by a gentleman who was quite au 

 fait in the matter. Rock-work, sea-shingle, alga, 

 and all were properly prepared and grown before 

 they were transferred into my wee glass ocean, 

 which was made perfectly fit for the introduction of 

 animals ere I began to collect live stock. 



Having succeeded well for a few years in keeping 



various zoophytes in first-rate condition, by means 

 of these unpretending glass bowls, in a house situ- 

 ated in one of the London squares (Tavistock 

 Square), I determined, on going to live in the 

 country, to try Marine Aquaria on a larger scale. 

 I was distant ten miles from the coast, so I set up 

 three kinds of marine homes ; in one I used the puri- 

 fied sea-water, procured from London ; the other 

 was filled with artificial sea-water, made with 

 Gosse's compound, the third stocked with sea-water 

 taken from off the beach at Southsea. This aqua- 

 rium caused me the most grief ; but it was great 

 fun also, to drive down from my little den at Ham- 

 bledon, and spend the entire day on the shore collect- 

 ing, though there was not much variety there, and 

 returning home in the cool of the evening, through 

 those green Hampshire lanes, the pony carriage 

 laden with jars of salt-water, and hamper full of 

 sea-weeds, — the hamper, which had in the morning 

 been the receptacle for our sandwiches and sherry. 



Sea-water, taken out at sea, some distance from 

 the shore is a very different fluid to what I got on 

 Southsea beach, or indeed from what I obtain here, 

 on the shore near Beaumaris. 



It had to be filtered through flowerpots stuffed 

 with pieces of sponge instead of corks, the sponge 

 left quite loose enough to allow of the water pass- 

 ing in a rapid drip down into the vessel below, 

 then allowed to settle'; then it had to be stirred up 

 again and refiltered, until it became purified from 

 all the filth and decomposed matter which it at 

 first contained; becoming in the end as clear as 

 crystal. 



Artificial sea-water requires the same kind of pre- 

 paration in a modified form ; it too needs filtering, 

 and testing, by means of gravity-beads. There 

 are two kinds of beads sold by dealers in aquaria, 

 called " specific-gravity beads." One of these balls 

 floats when the water is a right strength, and the 

 other sinks. Directly the floating ball begins to 

 sink, it shows the water is weak, and if the sinking 

 bead rises, add a littte fresh water until you see it 

 begin to fall again. Evaporation will cause an in- 

 crease in the density of the water. 



Gosse's formula, if you get the dry, in one-pound 

 packets, must be mixed in an earthen vessel ; some 

 pieces of sea-weed should be thrown in, and all left 

 to stand for a week or ten days (three gallons of 

 spring or river water to a pound of the dry prepa- 

 ration is the correct proportion). At the expiration 

 of this time, transfer the water into your tank, and 

 place the sea-weeds — I used small tufts of Viva 

 and Enteromorpha ; for I discovered they were the 

 best to have at first, though I afterwards intro- 

 duced other kinds for the sake of variety. Here 

 let me remark that all sea-weeds put in an aquarium 

 should be in a growing state, attached to small 

 pieces of rock. If you collect for yourself, go down 

 to the beach with wallet and hammer, when the 



