Anui. 1, 1866.] 



SCIENCE-GOSSIP. 



81 



it were, and after a time their skins split down their 

 backs ; they have become too big for their jackets, 

 like the boy in buttons who was perpetually (to the 

 dismay of his mistress) out-growing his clotlies, 

 and a pair of bright eyes, a body, and short semi- 

 transparent wings, which grow visibly, under one's 

 own eyes, appear. 



The expert way in which these young dragon-flies 

 use their neurated wings is really astonishing ; they 

 lift them gently, then spread them, and partially 

 shut them again, going over this process several 

 times, so as to allow of their becoming sufficiently 

 hardened for flight, when they suddenly rise into a 

 new element, evidently taught by a higher power 

 the purpose for which the exquisitely tinted fan-like 

 appendages had been given them. To return to the 

 planting of the vivarium, for it strikes me that, 

 seduced by the beauty of the dragon-fly, I have 

 made a step in advance of my subject. Some hardy 

 dwarf ferns, a few pretty grasses, and a pot or two 

 of flowers in bloom .'are the proper tilings for the 

 land department. A sprinkling of watercress seed 

 on the sand in the lake is a great improvement to 

 the water \ portion ; but the plants must not be 

 allowed to grow too large. A few fresh-water alga? 

 are very necessary articles in a vivarium, where 

 water insects are reared. The Oscillatoria? are use- 

 ful ; they aerate the water, and consequently keep it 

 pure. They are interesting objects as well. I have 

 already mentioned water snails— the one commonly 

 known as the " Trumpet Snail " is the best. 



There are some large water-beetles in my friend's 

 vivarium — the Hydropldlus Plsclus. They are a 

 harmless and exceedingly handsome sort, very differ- 

 ent to their cousin, Dytlscus marginalia, who is the 

 most voracious, impudent, aldermanic-looking beetle 

 living. I was much amused in watching the Hydro- 

 philus. Their eggs (sometimes sixty in number) are 

 held together by a gummy substance, and fastened 

 on by Mrs. Hydropldlus to a branch of some aquatic 

 plant. I like the caddis-worm in an aquarium 

 and was rather disappointed at not finding him in 



M 's vivarium. He is such a quaiut object, 



moving along with his domicile, formed of sticks and 

 stones, like a man in armour; and it is particularly 

 interesting to observe him emerging from his prison- 

 house. He turns his former abode into a kind of 

 raft, on which he rests till ready to take wing in his 

 moth-like character. It is sad that his winged life 

 should be of such short duration— a few hours only ; 

 but probably hours to one of the Ephemera reckon 

 like years. 



The Water Boatman is a very curious insect. He 

 lies upon his back, which is ridged exactly like the 

 keel of a boat, and rows himself about by the use of 

 his middle pair of legs. But leaving the water 

 portion of the vivarium and its aquatic inhabitants, 

 let us turn to those who occupy the land arrange- 

 ment of it. 



The Purple Emperor butterfly is a glorious 

 insect ; but, although you can rear him in a 

 vivarium, you will not be able to keep him 

 there ; he would die in a day or two in so con- 

 fined a space; for he loves to fly high, and may 

 be seen disporting himself in the sun upon the 

 oak ; but his caterpillar feeds upon the goat-willow 

 or sallow tree, and cau be easily kept if you provide 

 him with fresh branches of his favourite food, which 

 should be placed in the little bottles before men- 

 tioned. When about to pass into the chrysalis state 

 the larva suspends himself by a kind of web to the 

 under surface of some carefully-selected leaf, and 

 remains in what we should term a very uncomfort- 

 able position, head downwards, till his transforma- 

 tion is effected. The Peacock butterfly is another 

 beauty {his larva feeds upon the common stinging 

 nettle), and the pretty little blue butterflies— the 

 Clifden or Adonis, for instance — and the large white, 

 and the clouded yellow {Collets Edusa) are all very 

 suitable for a butterfly vivarium. I need hardly say- 

 that flowers must be introduced during the short 

 period of their perfect insect existence. The larva? 

 of a few moths may be placed in with advantage. 

 The Privet-hawk moth is a very handsome insect, 

 and its caterpillar is prettily marked. 



I must not forget to mention a few land-beetles, 

 such as the dear old Lady-bird, and the Rose beetle. 

 The eggs of the first mentioned, such tiny, yellow- 

 looking little things, are often found in summer on 

 the leaves of plants, always those on which they are 

 likely to find their future food (the Aphides). 

 Their larva? are not very attractive ; they are almost 

 black. The little Lady-bird, in its perfect state, still 

 affects the Aphides, and therefore does good service 

 in a greenhouse, or wherever there are plants in- 

 fected by these destructive pests. A dazzling little 

 sun-beetle or two, in their glittering coats of bronze, 

 and the rose-beetle, in his golden armour, are like- 

 wise very amusing, and add considerably to the 

 beauty of any vivarium. Helen E. Watney. 



BATH OR SCOURING BRICKS. 



PERHAPS a few remarks on this valuable 

 substance may prove interesting to some of 

 our readers, it being one of those articles of 

 every-day use, concerning which but few have 

 any definite idea. In the first place, it does not 

 come from or near Bath, as its name seems to 

 imply ; but is manufactured solely at Bridgewater, 

 iu Somersetshire, from the scouring-brick clay found 

 on the banks of the River Parrot for about a mile 

 above and below the town. 



This apparently strange freak of nature is easily 

 accounted for, as will be presently seen. The sub- 

 stance thus yielded by the river for a distance of two 

 miles is at once practically unique, and forms the 

 principal source of wealth to the town ; being ex- 



