Imagens das páginas

said that the series of experiments he had made upon different animals led him to the belief that the right side of the brain was more important for organic life than the left side. Although the two sides of the brain were precisely alike when the animals were born, by greater development of the activities one side came to be quite different from the other.

Geological Systems and Endemic Diseases. At the British Association at Liverpool, an important paper on the above subject was read by Dr. Moffat, showing that the soil has an influence on the composition of the cereal plants grown upon it, and on the diseases to which the inhabitants are subject. The district in which he practises consists geologically of the carboniferous and new red or Cheshire sandstone systems. The inhabitants of the first are engaged in mining and agricultural occupations, those of the latter in agriculture chiefly. Anæmia with goitre is a very prevalent disease amongst those living on the carboniferous system, whilst it is almost unknown amongst those residing on the new red sandstone, and consumption is also more prevalent amongst the inhabitants of the former. As anæmia is a condition in which there is a deficiency of the oxide of iron which the blood naturally contains, Dr. Moffat was led to make an examination of the relative composition of the wheat grown on soils of Cheshire sandstone, carboniferous limestone, millstone-grit, and a transition soil between Cheshire sandstone and the grit. The result of the analysis showed that the wheat grown on the soil of the Cheshire red sandstone contains the largest quantity of ash, and that there is a larger quantity of phosphates in it than in the soils of the carboniferous and millstone grit systems, and also a much larger quantity of oxide of iron than in either of them. He has calculated that each inhabitant on the Cheshire sandstone, if he consumes one pound of wheat daily, takes in nearly four grains more per day of the sesquioxide of iron than the inhabitant of the carboniferous system, who seems therefore to be subject to this great liability to anæmia in consequence of the deficiency of iron and phosphates in the food he consumes.

METALLURGY, MINERALOGY, AND MINING. What is Glaucopyrite?— This is a new mineral, which our American cousins have introduced us to. The American Engineering and Mining Journal gives a full account, of which the following is portion. Speaking of the kidney-shaped masses, it says, they are entirely surrounded with lamellar calc-spar; and, if this is removed with acetic or dilute muriatic acid, the surface appears to be formed by numerous, mostly very small, crystals, in comb-like aggregations. On the layer of these crystals, Sandberger could discern, with a magnifying glass, as a fundamental type, twins of two flat rhombic tables, lying crosswise to each other, and presenting the habitus of cerussite-twins of similar combination ; besides these, triplets can be distinctly recognised. The streak of the fine granular masses is shining, but the lustre of the crystal faces is feeble, except certain faces supposed to be normal prismatic and brachy diagonal prismatic, which have a strong metallic lustre. The colour of the mineral is light lead-grey to

tin-white, the streak greyish-black; hardness, 4.5; sp. gr. 7.181. In contact with the air, the mineral tarnishes slowly, first assuming a blackish, afterwards a yellowish-brown, and finally a blue colour. An analysis made by R. Senfter, in the laboratory of Dr. Petersen, gave the following result:Sulphur, 2:36; arsenic, 66-90; antimony, 3.59; iron, 21:38; cobalt, 4:67; copper, 1:14: total 100·04. The new ore belongs, consequently, to the group of arsenical pyrites, and comes nearest to the mineral from Wolfach, which Sandberger identified with Breithaupt's geyerite. But, as neither form por hardness, nor specific gravity and colour, are the same in both, and as, moreover, the copper observed in the new mineral is wanting in geverite, Sandberger proposes, for this new ore from Guadalcanal, the name glaucopyrite, and gives for its composition the formula

FeS+12(Co) AS

[ocr errors]

The Rochage" of Cast Iron.An interesting letter on this subject appears from “T. B." in the Chemical News of August 5. It says that this curious phenomenon is well-known to those engaged at blast-furnaces. The sparks are known by the workmen as “jumpers," and their presence is usually held to indicate an approximation to white-iron. These sparks are absent during the running of grey-iron from the furnace, and only begin to make their appearance when the iron is about No. 4, the usual degree of greyness preferred in South Staffordshire for puddling. The sparks are best observed during the running of white-iron from the furnace, especially if the molten metal is not very fluid, at which times he has frequently observed a vast number produced, particularly in the channel ; and sometimes, after the pigs have "set," little jets of sparks are continuously discharged for many minutes, which discharge is accompanied by a hissing sound. M. Caron's view may probably be correct, but be is inclined to attribute the production of these sparks to the combustion of carbon, and not of iron, as there is an entire absence of the peculiar scintillations displayed by burning iron. Yet one would almost be inclined to believe that grey-iron, which is supposed to contain uncombined carbon, would be more likely to exhibit this appearance than would white or mottled-iron. Yet, in grey-iron, and even in over-grey, or “Kishy” iron, there is an entire absence of these sparks.

Important to Paraffin-Oil Producers.-The Association for Mineral Oils at Halle, in the Saale, desires to obtain information relative to: 1. The best information concerning the chemical means of purifying crude paraffin cakes, so that the loss of paraffin does not thereby rise above 5 per cent. 2. A contrivance whereby materials containing paraffin may be cooled down at any season of the year to at least 5° C. In reference to No. 1, among other conditions are that such substances as colourless tar oils, benzine, and, generally speaking, any substances which either dissolve or alter parallin, are excluded from use; the operation, moreover, ought to be readily executed and suitable for working on the large scale : the paraffin should be free from smell, and be of a bluish-white colour. In reference to No. 2, the contrivance ought to be such as to enable to cool down daily at least 500 cwts. in quantities of 5 cwts. at a time. The Association is inclined to give two premiums, each at 7501. value, for the best of the contrivances asked for, the

time being fixed for January 1, 1871. Apply to the Mineralöl-Verein zu Halle a. d. S. Prussia. The committee of examination consists of several parties, among whom is M. A. Riebeck, at Halle.

Mineralogical Work.The American Journal of Science and Art (July), gives a long account of several new mineralogical discoveries of Mr. C. U. Shepard, sen. They are summed up as follows: A new variety of columbite, found to consist, in 100 parts, of metallic acids, 78:30; protoxide of iron, 13 86; protoxide of manganese, 7.72; traces of tin. Unknown mineral (microlite ?) in Haddam columbite. New locality of bismuthine and bisinuthite, in Haddam. Metallic acid in microlite. Redondite, a mineral found in Redonda Island, and containing 44 07 per cent. of phosphoric acid, 24.73 per cent. of water, and oxide of iron and alumina. Phosphoric acid in the diaspore of Chester, Mass.; the mineral here alluded to is mainly hydrate of alumina, containing only 0:32 per cent. of phosphoric acid. The Pelham vermiculite contains, in 100 parts, alumina, 14:0; magnesia, 1368; peroxide of iron, 320; silica, 24:0.

The Khettree Meteorite.—The Chemical News of June 17 contains a very long account, by Dr. Waldre, F.C.S., of this peculiar meteorite, which seems to have fallen very largely. The stone is partly of a light bluish-grey colour, partly of a much darker grey; in some places the two portions lying in contact like two strata, in others nodules of the one imbedded in the other. The broken surface is studded over with metallic particles, many of them having a bright metallic lustre; and there are also observable, by aid of a lens, spots of a yellowish or brown colour, from oxidation of the iron, and granules of a greenish-yellow colour and translucent appearance, probably olivine. Spherules of earthy matter are also visible, and round cavities in which others have been inbedded. When coarsely powdered, the spherules are more visible; and, when more finely powdered and examined under water with the lens, the lighter portion of the stone exhibits a considerable quantity of a nearly white crystalline matter, the particles of which are tolerably uniform in size, mixed with small angular fragments of black, brownish, opaque, and greenish-yellow translucent minerals, and irregularly-shaped but rounded particles of iron. The dark grey portion exhibits the same appearances, but with a much larger proportion of darkcoloured earthy minerals. The particles of the iron, having resisted trituration, now appear much larger than the others.

The Action of Heat on Diamonds.-A very curious influence exerted by heat upon diamonds bas been noticed at the works at St. Helen's, recently visited by the British Association. When a diamond is used to cut hot glass the diamond will only last for one day, and it assumes a milky appearance. The diamonds in constant use for cutting cold glass last about three Juonths. Each diamond costs from 358. to 458., and is about three times the size of an ordinary glazier's diamond. Hot glass is cut more readily than cold glass.

Improvements in Heary Forgings.—Lieut.-Colonel Clay read a short paper on improved appliances for the production of heavy forgings at the Lirerpool meeting of the British Association. Considerable difficulty had until recently been encountered in the economical forging of large solid masses of iron, which was an engineering desideratum of vast importance. The old

constructions of furnaces were most imperfect and unreliable, some of them requiring renewing once a fortnight. Mr. Siemens had introduced the principle of heating large forges by means of gas, which attained intense degrees of heat and saved at least 50 per cent. in fuel. Until, however, the author of the paper attempted the experiment at the Mersey Iron Works, Mr. Siemens's principle had not been applied to the heating of large solid masses of iron. His application proved completely successful. He had also introduced improved facilities for the handling of the hot masses of iron, and for affording more working space for the men; and he had introduced a hammer with a clear unfettered fall.

Rolling Axles.-Mr. Alfred Bowater submitted a paper descriptive of a new machine, existing in model, for the shaping of railway axles by rolling pressure. Whereas by the steam-hammering process an axle required half an hour in shaping, this rolling process would effect it in a superior manner in two minutes. The rolled axle was not only superior in quality, but was more uniform in size, and could be produced much more cheaply. The machine consisted of thiee rollers, which were regulated so as to gradually press closer together, thus reducing the diameter of the bar and extending its length until shaped to the size required. Axles of any length could be thus rolled, with collars at any part of the tyre. The rollers were geared to revolve all in the same direction, and their friction imparted motion to the axle. The rolling process would obviate those flaws in axles which occaonally caused appalling disasters on railways.


An Erecting Binocular Microscope. - An instrument of this kind, which promises to be the binocular of the future, has been devised by Mr. J. W. Stephenson, and described to the Microscopical Society. It would be impossible to give a satisfactory explanation of the instrument without a cut, so we must refer our readers to the Monthly Microscopical Journal for August for further details.

The Presidentship of the Quekett Club.—The club has done wisely and well this time in its selection of a president in choosing Dr. Beale. No one could be so well qualified for the task. Dr. Beale is, without any question, the first microscopist in England. It is greatly to be regretted that his engagement on the evening of which the Royal Microscopical Society meets prevented his accepting the presidentship of that institution.

Photographs of Nobert's Lines.-Dr. Woodward, of the United States' Army Medical Department, has just presented to the Royal Microscopical Society and to a few private friends, four admirable photographs of the above. The first represents the 1st, 2nd, 3rd, and 4th bands of the 19 bandplate, magnified 1,200 diameters by Powell and Lealand's ieth immersion. The second represents the 8th, 9th, 10th, and 11th bands of the same plate, magnified 1,100 diameters with the same objective. The third displays the 13th, 14th, and 15th bands of the same plate, magnified 1,100 diameters with the same objective ; and the fourth contains two photos, one a large one representing the 19th band of the 10 plate-band, magnified 1,100 with Powell and Lealand's ith immersion, and the smaller an enlargement of part of the other to 2,750 diameters.

Synchata under the Microscope.—Dr. Hudson, in a recent article on this subject, in the Monthly Microscopical Journal, says that when once Synchata is placed between two plates of glass in a drop of water sufficiently small to keep it within the field and tolerably within the focal length even of an inch objective, its characteristic motions cease; it swims incessantly round and across its prison, and at such a rate that the eye gets weary of following it. By gently compressing it one good view can be obtained, but then it is always the same, or at all events can be only slightly altered by reversing the compressorium. In consequence of this no attempt has been hitherto made to describe the top of the head, or to delineate the front or side view. Its outline when swimming with either dorsal or ventral surface at right angles to the line of sight is that of a boy's kite; and exactly where the kite's tassels would be are two movable lobes fringed with a ring of powerful cilia, by means of which the creature performs its various antics in the water. Though the cause of ciliary action seems to be a mystery, yet the various ways in which the cilia of the lobes must work to produce Synchata's motions admit, he thinks, of being explained.

The Anatomy of the Chiton.-In the Archives néerlandaises (t. iv.) M. W. Marshall gives an interesting account of the above. He describes the tests as composed of two parts, covered with an epidermis : the articulament and the segment. The former is composed of four layers; the deepest of these consists of calcareous prisms placed perpendicularly to the axis of the animal, and further it presents the several zones having different degrees of colour ; the second layer is harder and thicker, and is composed simply of very fine granules, it is porcellainous, translucent, and of a bluish-white colour; the third layer is, like the first, composed of prisms placed at right angles to the axis, viewed in section they have the appearance of being finely striated ; the upper layer is of a very peculiar nature. The author says that each articulus buccalis is seen to consist of ten peculiar triangular bodies whose points converge to form the point of the articulus. Each of these triangles in its turn appears to be formed of a number of needles, so arranged that they help to give the triangular shape to the body, and are themselves constituted like a feather of a shaft and minute crystalline barbs, and possibly barbules. M. Marshall gives a series of figures depicting these singular structures, and in fact enters into so many details as to render it impossible for us to give a just abstract of his views.

Microscopic Illumination. Mr. Wenham and Dr. Pigott.—The result of the present controversy is at present undecided. Whether Mr. Wenham or Dr. Piyott is right remains we think to be proved. Dr. Pigott is certainly gaining ground, but then the question may be asked, Is not this because Mr. Wenham is remaining quiet? We cannot venture to say on whose side right lies, but the following quotation from a paper by Mr. Wenham may be of interest. “It is scarcely to be expected," says Mr. Wenham, “ that those who have not in some degree been practically familiar with the construction of object-glasses, can be fully aware of the value of the mercury

« AnteriorContinuar »