SCIENTIFIC INTELLIGENGE. 



[1852. 



alluvial deposits, formed from extensive ubrasion of llie rods beneath 

 the waters of past ages, or it is disseminated tbroiigli the solid rock. 

 Allhougli, in Bomc localities of North Devon, gold may he found in 

 alluvial depc sits, yet, in all probability, it is principally confined to 

 the rock ; and, owing to the prevailing error to which we have just 

 alluded, it is believed by the uucxpcrienccd that much gold is only to 

 be expected from very high mountains, and that it is, consequently, 

 absurd to anticipate that the " mole hills' ' of Devonshire will com - 

 I)ensate for the expense of working. This argument, liowover, is not 

 sustained by general experience or actual facts. In the Ural, which is 

 in the heart of a large continent, and, therefore, may be expected to 

 reach a considerable height, some of the most prolific sources of tlio 

 gold are at an elevation under 1000 feet above the level of the sea. 

 Miask and Ekaterinbiirgh are each below that level, while Kyshluirsk 

 is only 630 feet, and Bogoslovsk 500 feet. Although there are high 

 jioints in the Ural, as well as in Australia and California, at which 

 gold is found, yet the most productive localities in ali these regions 

 arc of very moderate clcvali'jn. Tlie gold district now revealed in 

 Devonshire reaches an elevation of 700 feet above the sea. There is 

 nothing vaUd, therefore, in the assertion of "mole-hills" being pre- 

 Bumj^tive evidence of the non-existence of gold ; and we do not 

 hesitate to declare our firm conviction that a brief time will cst.nblish 

 the Britannia gold-flcld as one of several localities among the hills of 

 North Devon in which gold will repay the enterprise and industry of 

 those who search for it. — Mining Journal. 



IWcanic Eniption in the Smnlwich Islands. — By an accurate measure- 

 ment of the enormous jet of glowing lava where it first broke forth 

 on the side of Mauna Loa, it was ascertained to be 500 feet high. 

 This was upon the supjiosition that it was 30 miles distant. Wo are 

 of the opinion that it was at a greater distance — say from 40 to GO 

 miles. With a glass the play of this jet at night was distinctly 

 observed, and a more sublime sight can scaiccly bo imagined. A 

 column of molten lava, glowing with the most intense heat, and 

 projected into the air to a distance of 500 feet, was a sight so rare, and 

 at the same time so awfully grand, as to excite the mo.st lively feelings 

 of awe and admiration, even when viewed at a distance of 40 or 50 

 miles. The diameter of this jet is supposed to bo over 100 feet. In 

 some places this river is a mile wide, and in others more contracted. 

 At some points it has filled up ravines of 100, 200, and 300 feet in 

 depth, and still it flowed on. It entered a heavy forest, and the giant 

 growth of centuries was out down before it like grass before the 

 mower's scythe. No obstacle can arrest it in its descent to the sea. 

 Mounds are covered over, ravines are filled up, forests are destroyed, 

 and the habitations of man are consumed like flax in the furnace. 

 Truly, " He toucheth the hills, and they smoke." We have not yet 

 hoard of any destruction of life from the eruption now in progress. 

 A rumor has reached us that a small native village has been dosti'oyed, 

 but of this wc have no authentic intelligence. Two vessels had sailed 

 from Hilo, both filled to their utmost capacity with ]5cople who desiied 

 to witness this great eruption. The eruption sceras to have broken 

 out through an old fissure, .^bout one-third down the side of Mauna 

 Loa, on the north-west side, and not from the old crater on the 

 summit, called Mocquowcoweo. The altitude of the present eruption 

 is about 10,000 feet above the level of the soa, and from the bay of 

 Hill) (Hyruu's Bay) must be smno 50 or GO miles. If it succeed in 

 leaching the ocean at the )i"inl supposed, after having filled up all 

 the ravines, gulches, ami inequalities of a very broken country, it will 

 undoubtedly bo one of the most extensive eruptions of modern times. 

 — 2'olynciian. 



Iron. — In the recently discovered Iron Districts of Cleveland, York- 

 shire, the beds are found to lie ncaily level, varying iji thickness from 

 12 feet to no loss than 20 feet of iroiibtouo, the most remarkable 

 feature is that the ore is gut by open quarrying ; and is estimated that 

 10,000,000 tuns may bo got wilh the same facility. Tliero is no lime- 

 stone 01 coal iu the district though geologists consider that they may 



yet be readied. The operations were commenced in April 1851 and 

 the tralHc of ironstone up the Stockton, Darlington Railway has siuco 

 been at the rate of 200,000 tons per annum. 



ZOOLOGY- 



Itifiisoria the Larvcc of Intestinal Wonns. — Among the most interest- 

 ing of Agassiz's discoveries in embryology and the metamorphoses of 

 the different lower orders of animals, the fact that Infusoria are 

 nothing more than the Larva; or young of Intestinal Worms, is perhaps 

 one of the most important. Agassiz remarks that it is curious that the 

 two types of the Animal Kingdom so long considered as the funda- 

 mental supporters of the theory of spontaneous generation should have 

 finally been brought into such close connection, and that one of them 

 — the Infusoria — should in the end turn out to be the earliest condition 

 of the other — the intestinal worms being the parents of the Infusoria. 

 Tlic latter class may now be considered as entirely dissolved. — Silli- 

 man's Journal, May, 1852. 



Artificial Breeding of Fiah. — At a recent meeting of the Society of 

 Arts, a paper was read by Mr. W. Boccius, "On the AniScial Breeding 

 and Rearing of Fish, and the method to be adopted to jireserve and im- 

 prove the Fisheries of this country, and also of the colonies." Mr. Boc- 

 cius commenced by calling attention to the decline which has taken 

 place in all the fisheries of the United Kingdom, and jirocceded to point 

 out thu means by which any sort of fish might bo restored to a stream or 

 river in one season, and the eggs transmitted from one part of the king- 

 d<ini to .another, or from one country to .inothcr, without the least injury 

 to them. The main feature in artificial breeding was to have a pure 

 S]iriiig of water, uncontaniinated wilh vegetable or animal matter, at a 

 temper.ilure of 54 ° to 5G ° . At this warmth the salmon egg came into 

 life iu 100 days, trout in 50 days, and many other sort of fish in 42 days; 

 but this was only the case when the water underwent no change of 

 temjiorature. By the plan of artificial spawning which he proposed to 

 ado])t, the crossing of various breeds of fish of distant countries might 

 bo elTected. Having found a pure spring of water, his method was to 

 place boxes containing the spawn bed in the stream, in such a manner 

 that there should bo a constant flow of fresh water through the boxes. 

 IIo next took two fish, and separated tho spawn and the milt from 

 them into a basin containing sufficient water to dilute the milt that 

 might be absorbed by the egg. Tho eggs were then placed in the 

 coarse clean gravel, three inches deep, and allowed to remain so until 

 they were bred out. The brood was then left — of silmon, 30 days ; of 

 trout, 15 days — and afterwards put into a yearling stream, the small 

 left to migrate, and the trout sent out into tho main stream or river nt 

 tho season following. If his system of artificial spawning were adopt- 

 ed, a vast amount of labour would be required, and a great additional 

 quantity of food produced, while the gain to the proj.rietor of the 

 water would bo much increased. Supposing 300,000 eggs to bo spawn- 

 ed, the produce of 12 s.alnion, of 25 lb. each, in two years these fi»h 

 would give 3,000,000 lb. weight, and at that time they in turn would 

 bo capable of depositing the enormous quantity of three billions of 

 eggs ; and yet, with this great i)rocreativc power, the salmon and all 

 other fish were fast decreasing in our rivere and streams. It was with 

 a view to remedy this evil, that he desired to carry his jilan into effect, 

 and ho had already adopted it successfully on the estates of tho Duke 

 of Rutland, the Duke of Devonshire, Earl Ducie, and many other pcr- 

 .sons of distinction and properly in England. At the conclusion of the 

 paper a vote of thanks was passed to Mr. Boccius, and after some 

 little oUscussion tho business of the evening terminated. 



Nati'kalists will be pleased to learn, that in the course of the past 

 month a young grass paroquet, of the Australian species, has been 

 ]iroduced in tho Zoological Gardens, Regent's Park ; and also a pair of 

 Mandarin ducks. One of the ostriches recently brought from Egypt, 

 has, doling tho month, dc)Hisitcd four eggs, which have been ]ilaced in 

 one of Cautelo's llydro-lncubators. The result of the ex|ieriinent is 

 ex; ectod to bo known iu n few days, and is awaited with cousideiablo 

 iutoicst. 



