324 



EECREATIVE SCIENCE. 



movable in the ordinary way with soap and water; 

 a greater heat would spoO. the hairs, especially of 

 hog-tools. 



Restoration of Fractured Bells. — Since the 

 two renowned failures in connection with the great 

 bell of the Westminster Palace, scientific men have 

 been engaged in numerous experiments and inquiries, 

 with a view to reduce to certainty the at present un- 

 certain details of the composition and mechanism of 

 bells. In one instance, a result has been arrived at, 

 which renders it probable that a cracked bell, how- 

 ever large, may be restored to perfect working order. 

 At a recent meeting of the Institution of Civil Engi- 

 neers, Mr. Varley exhibited a cracked bell, which had 

 been recovered by soldering the crack with tin, so that 

 it was as sonorous as before. The principle of the 

 restoration is this : — Tin when heated above the boiling 

 point to nearly a red heat, dissolves copper, and com- 

 bines with it to form an aUoy. The bell, being first 

 soldered with tin, must be kept at a red heat for a 

 certain length of time, during which the copper in 

 the bell-metal, in the parts adjoining the crack, min- 

 gles with the tin with which the crack was soldered, 

 and thus the soldering becomes homogeneously com- 

 bined with the mass, as if a part of its original struc- 

 ture ; and the bell resumes the utterance of its original 

 tones. 



Propagation by Candlr-heat. — Among the curio- 

 sities of horticulture, is the newly-introduced method 

 of propagating plants by the heat of a candle-flame, 

 which is the result of experiments by one of Mr. 

 Noteworthy's friends. The useful invention known 

 as the Waltonian case was formerly heated with an oil- 

 lamp or gas-jet, and the object of obtaining a candle 

 suited to it was to render it available as a recreation 

 for the sick-room, where the invalid could watch the 

 growth of the plants, and by the definite number of hours 

 which the candles burn, entrust the management of 

 the heating apparatus to a domestic wholly unskilled 

 in the operation. Just as the candle or mortar heats 

 the boiler on which the plants are placed, so it would 

 prove a cleanly and certain source of heat for many 

 chemical operations, and for the sick-chamber, and 

 even for the dinner-table, to keep the venison hot. 

 The next step in this direction should be to adapt an 

 efficient heating apparatus to Wardian cases, to enable 

 amateurs to preserve, during the winter, many of the 

 choice silver and gold ferns, and other exotic Filices, 

 that too commonly perish through having to endure 

 too low a temperature in dwelling-rooms and en- 

 trance-halls. In the March Number of the Floral 

 World will be found a description, with figures, of 

 the Waltonian case as adapted to be heated with the 

 candles. 



EoCKWORK FOR Aquaria. — Several correspondents, 

 who have inquired of Mr. Noteworthy on this subject, 

 are informed that the best of all materials for rockwork 

 in aquaria is mica schist, because on that kind of rock 

 the confervoid vegetation appears the soonest, and en- 

 dures longest, so as to provide an abundant supply of 

 oxygen to the animal inhabitants. Coke washed with 



Portland cement and pumicestone ia often used, be- 

 cause it is lighter than other materials, and the tanks 

 made on the old plan are unable to bear the pressure 

 of a large mass of rock, and without rock where is the 

 nidus for spontaneous vegetation ? Whenever cement 

 can be dispensed with the better, and it is not a diifi- 

 cult matter to build up rockwork wholly without it. 

 The best cement is Portland, which does not crumble 

 if mixed in small quantities at a time, and used 

 quickly. As the tanks are now made with Mr. Lloyd's 

 joints and elastic cement (patented, and kept secret^, 

 they are capable of bearing without strain as much 

 rockwork of any kind as can be got into them. Mr. 

 Noteworthy has recently inspected Mr. Lloyd's new 

 arrangements at Portland Eoad, Eegent's Park, and 

 rejoices to be able to bear testimony to the assiduity, 

 enterprise, and scientific skill of that eminent pur- 

 veyor of stock to the whole aquarian world. 



The Great Tide of the 8th. — To enter fully 

 into the subject of tidal phenomena would be out of 

 place here ; but as several of Mr. Noteworthy's friends 

 ask for a reason in reference to the great tide of the 

 8th, a few words will sufiice to explain it. The attrac- 

 tion of the moon heaps up the waters of the earth, and 

 if the earth and moon were stationary, the waters would 

 assume the form of an oblong ellipsoid ; but as neither 

 are so, there is never time for the spheroid to be formed. 

 The efi'ect of the motion of the attracting power is to 

 cause a vast flat wave, which follows the apparent mo- 

 tions of the moon ; when the higher or lower parts of 

 this wave strike our coasts, we say it is high or low 

 water. The sun exercises also a great attractive force, 

 and sometimes the wave formed by the sun is added to 

 that formed by the moon, when sun and moon act 

 together in the same direction ; and at other times the 

 sun-wave is formed transversely to that of the moon, 

 and the lunar-wave is thus weakened ; hence we have 

 spring and neap tides. On the 7th of March last the 

 moon was at the full, hence sun and moon were on 

 opposite sides of the earth, and a spring-tide would be 

 the consequence, the waters being equally heaped up 

 on the two hemispheres. But the moon was also in 

 perigee — that is, at a point of her orbit nearest the 

 earth, and the sun being at the same time at the 

 equator, on his way to inaugurate the northern sum- 

 mer, the two bodies acted together with more than 

 usual force, and so equally as to neutralize eac'n others 

 action the least possible. Thus a well balanced and 

 augmented attraction on opposite sides of the earth 

 caused the tide-wave to rise higher than ordinary; and, 

 as a consequence, there was a considerable amount of 

 excitement at seaports, and on the banks of navigable 

 rivers, at the deviation of the waters from their cus- 

 tomary levels. As the great tide was predicted by 

 astronomers, much property was saved from destruc- 

 tion by the precautions taken in anticipation of the 

 event. In September next, when the sun will be again 

 on the line to act in conjunction with the moon, the 

 great September tide will afford a good opportunity to 

 visitors to the coast to study the subject, as well as to 

 make good gatherings of manne objects for the 

 aquarium. 



