« VorigeDoorgaan »
matters; and that while it is the custom to call a Campanula by the hard word, and a Tropæolum by the wrong word (Nasturtium, which is the name of the water-cress), no reasoning will induce a change; we are far from flattering ourselves that any observations of ours will have this effect, nor is it a matter of the slightest consequence by what name an object is designated, when it is spoken of without reference to others; but the attempt to restore ambiguous trivial names in scientific works, while we are endeavouring at the same time to inculcate the necessity for an accurate discrimination in minute particulars of habits, structure, properties, &c., of animals, must have a mischievous tendency equally to knowledge and to taste.
Suppose, for example, that English names were adopted, and that desirous of avoiding such barbarisms as mammals, exogens, &c., we translated the classical names; the animal, Agouti, which is of the order Rodentia, class Mammalia, would be described as belonging to the order Gnawers, class Sucklers. Admitting this phraseology to be desirable, what must we do to define a slug? To be consistent, we must call it a shell-less, land, gill-less, belly-footed molluscous animal, winding up with an adjective, for which no human ingenuity can find an English equivalent in less than ten words; would it not be better in every respect, even in popular works, to define the creature as a species of the genus Limax, of the section terrestrial Pulmonia, class Gasteropoda, division Mollusca? for it is clear that the person who could really comprehend the English definition, must also be sufficiently master of classification to comprehend the latter; and if he did not know the etymology of gasteropoda, he would at least have become familiar with it as a term for a large class of Mollusca, the character of which is to have the organ of locomotion on the part analogous to the belly of more perfect animals.
Our illustrations have been entirely drawn from natural history and physics, because it is in science alone that we think the adoption of vernacular terms to be particularly deprecated. With regard to mere technical words in the arts, custom and the good taste of individuals are sufficient guides as to the propriety, or otherwise, of adopting Greek and Latin names. We smile at the appropriation of Caminology, by the French, to express the trade of a chimney-doctor, or of lithologic arts to designate those of a bricklayer and mason; but it would be difficult to offer
any valid reason against their adoption, while so many others, not more necessary, are tolerated; why do we ridicule an
Emporium for Blacking,” and not “a Bazaar?" And are we not guilty of downright
" nonsense in styling a collection of foreign animals placed in a pleasureground the Zoological gardens? The fact is, it is the worth of the subject that sanctions a name in one case, and makes it contemptible in another; but being willing to leave these comparatively unimportant matters to a censor of taste, we hope that science will be left to recruit its nomenclature from those languages in which it drew its first breath, until our own undergoes such a revolution as will better fit it for the purpose,-a revolution which every one would deplore, but which will be accelerated by injudicious advocates.
SPHERICAL FIGURES. The principles on which the circles of the sphere should be represented, are very simple; and yet the practice of mathematicians, who, of all men, ought most to attend to such matters, seems to indicate a total absence of all principle whatever in sketching their diagrams. The distorted and unmeaning figures which are often given to illustrate spherical problems, are sometimes really painful to look upon; and this not only in the drawings of the young, but of the most able mathematicians. I hope this will be a sufficient apology for the few following remarks.
The best mode of representing spherical figures, except when a particular mode of projection is implied in the mode of reasoning, is the common perspective representation on a plane at right angles to the line drawn from the eye to the centre of the sphere. A case of this is the orthographic projection; and the limit on the other side is the stereographic. The latter is too much distorted to furnish any idea of the magnitude and figure of the curve projected'; and perhaps the orthographic is of all kinds the best; though the perspective taken with the eye at the distance of fifteen or twenty times the diameter of the sphere may do very well. In all cases where the projecting point is without the circle, the figures into which the circles of the sphere are projected, are ellipses, and they are all concave towards the centre of the sphere. Moreover, the more inclined the planes of the circles are to the principal line of vision the greater will their minor axes become.
Those great circles which pass through the point in which the principal line of vision cuts the surface, will be projected into straight lines a construction which should, except several such circles, symmetrically related to the figure, pass through one point,-be generally avoided, as it renders us liable to mistakes, when actual straight lines occur in the investigation. This precaution is unnecessary when less circles pass through that point, as there is then no liability to mistake, these being projected into ellipses.
The parts of the figure which lie on the hidden hemisphere should be dotted, and form continuous ellipses with those on the visible hemisphere; and it would be well to mark the corresponding points with the same letters, accenting those on the dotted part of the figure. This is in strict accordance with the practice of the best French writers on Descriptive Geometry.
When the figures represented are other than circles, the best mode of marking a few leading points of them through which the projection is to pass, is to draw radiating great circles from the upper point of the great circle parallel to the plane, and projecting the points in these upon the paper as nearly as can be done by estimation, trace the curve through them. Of course, if we wish to have the figures constructed accurately, we must proceed in the usual manner taught in works on Perspective: but as this, especially during the study of a proposition, is altogether unnecessary, and as it is desirable that we should, at least, approximate in general character and appearance to the thing intended, the preceding remarks may not be altogether without their use. Vicarage, Overton, Sept. 16, 1836.
P.T. VOL. II.
English Industry in Scientific Research. he, “I saw the fact with my own eyes.
Dr. Jeng, an Austrian physician, saw it “Of the fifty-five simple substances re- also, and remarked at the time what a cognised in physics, twenty-two, and of the forty-five metals, seventeen, have very extraordinary circumstance it was.
I therefore give it as perfectly correct." been discovered in England." Our
Our readers may remember that the countrymen may plume themselves, if
late Sir J. Banks and Sir C. Blagden, they please, on this fact. We sincerely remained in an oven with a shoulder of wish that they could lay claim to an equal mutton till this was thoroughly baked. proportion of the whole of the great
The power of enduring great, though physical laws, and of the formulæ by not abrupt changes of temperature, which those laws are expressed,—the
has been put in a striking point of results of profound analytic investiga- view during the late Polar expeditions. tions based on carefully-repeated ex- In the winter of 1833-4, Captain Back periments, and requiring more intensity of mental exertion than the discovery Reliance, on the Great Slave Lake,
and his party, while residing at Fort of a new body, which is most commonly
were exposed to an average temperafortuitous.
ture of — 33° (65° below the freezing New Method of cultivating the point,) during the whole month of Cerealia.
January, and on the 17th, the ther
mometer was as low as - 70°, (102° – MM. EDWARDS and Collin, in a joint fr. pt.) A six ounce bottle of sulphuric memoir on agricultural chemistry, have ether was laid on the snow; in fifteen shown, that by sowing our principal minutes the interior upper part of the species of cerealia in the summer sea- phial was coated with ice, and the ether són, a profitable harvest of straw, or became viscid and opaque; a similar fodder, may be obtained the first year, bottle of nitric ether indicated the same the plants not flowering, owing to the effects in two hours. Pyroligneous acid elevation of temperature; and that the froze in thirty minutes at a temperature following season, the same plants, expe-of-57° (89o – fr. pt.); a surface of four riencing the usual gradations of tein- inches of mercury, exposed in a common perature, will furnish an abundant har
became solid in two hours. vest of grain. This proceeding has
“On the 4th of February, the tempebeen successfully adopted with rye, by rature was - 60° (92o — fr. pt.), and there a member of an agricultural society at being at the same time a fresh breeze, Valenciennes; he last year sowed the was nearly insupportable: with eight rye, and towards the close obtained two large logs on the fire, in a small room, I cuttings of green fodder; this year the could not get the thermometer higher same plants flourished so well, that they than + 12° (20°— fr. pt.,) and ink and had attained a height of seven feet a paint froze on a table placed as near the month before the usual time of harvest. fire as I could bear the heat"- -"the skin Great variation of Temperature borne of the hands cracked and opened into by the Human Body.
unsightly gashes, which we were obliged
to anoint with grease. On one occasion, At the Hot-Baths of Kukurli
, at after washing my face within three feet Broussa, in Bithynia, (the natural tem- of the fire, my hair was absolutely clotted perature of which is as high as_183o... with ice before I had time to dry it." 1894° Fahr.,) the Duke of Ragusa On the 25th of January, the thermostates (in the notice of his Travels in meter was at - 18° (50° – fr. pt.,) and on the East, lately communicated to the the 26th it had risen to + 22°, (10° —-fr. Académie des Sciences by M. Arago,) pt.,) while on the following day, it fell that he saw a Turk remain for a long again to - 49° (81°– fr. pt.,) thus, in time in a water-bath, whose temperature the course of twenty-four hours, an was 165° Fahr. This fact, which ap- inequality of temperature of 71° had pears incredible, the Duke affirms in been experienced ; on the 8th of Februthe most positive manner; "for," says ary, a difference of 38° took place in the
same time, and on the 21st, of 43”. On works of MM. Biot, Gay-Lussac, Pouthe 3rd of April the thermometer was illet, &c.; he then adds, “but notwithat + 51°, (19° + fr. pt.,) and on the standing these authorities, such a view 28th of May, it stood at + 81° (49° + of the subject is incorrect, in fact, the fr. pt.,) and yet on the 1st of that temperature of the vapour which rises month it had been down at 11° (43° from a saline solution in ebullition, is - fr. pt.) When the party set out independent of the nature and of the on their expedition in the month of quantity of the salt dissolved; it is, June, they travelled over the ice on the under the same barometric pressure, lakes and rivers, and yet were com- absolutely the same as that of the vapour pelled to journey by night, because the which rises from pure water." oppressive sultry heat during the day M. Rudberg had been led to make was so great, as to fatigue the men, and some rigid inquiries into the subject, knock up the dogs; and yet the ther- after having found that water put into mometer frequently fell' below the ebullition, either in vessels of glass or freezing-point, during the night. of metal, always gives out, under the
same atmospheric pressure, vapour of New Link between the Great Divisions precisely the same temperature, although of Organized Beings.
the water itself, when it boils, be, as M. M. GUERIN has detected under each of Gay-Lussac had already observed, actuthe first rings of the abdomen, in the ally hotter when it is in the first kind of Machilus polypoda, of the order Thy- this case the difference of the tempe
vessels than when in the second. As in sanoura, orders of respiration analogous ratures of boiling water is produced by to those found under the abdomen of many of the Crustacea; in all other an unequal adhesion of the water to the
interior surfaces of the vessels, it would respects the insect perfectly agrees with the characters of its class.
appear more than probable that, in the
same manner, the attraction of the salt Vapours of Saline Solutions and of by the water raises the solution only to Water, same in Temperature.
a temperature superior to 212°, without
exercising any analogous influence on It is generally admitted, that the aqueous that of the vapour. The experiments vapour which is disengaged from saline of M. Rudberg have fully confirmed this solutions in ebullition, has exactly the conjecture. same temperature as the superior stratum He began by constructing an appaof the solution, and that thus the vapour ratus which could not be affected by possesses, but in this case only, an the influence of any external disturbelasticity equivalent to the atmospheric ing circumstances; he then made his pressure, a less, consequently, than it experiments on different days, and would have attained at its maximum of under different atmospheric pressures. density, when its temperature would be His intention being principally to asmuch higher than 212o. It appears certain by these means, if the tempealso natural, that each rising bubble of rature would follow a corresponding vapour should acquire immediately the march to that of the barometer, because, temperature of the fluid which surrounds in this case, it would be the best proof it on every side, and should continue at that the cause, through which the the same time to be subject to a certain vapour possesses a temperature inferior expansion until its elasticity becomes to that of the saline solution, and exequal to the atmospheric pressure. actly the same as that of the vapour This also perfectly agrees with what of distilled water under the same happens, when vapour is disengaged pressure, ought not to have been sought from saline solutions at a low tempera- in the refrigerating action of the air, but ture, by the effect of evaporation; the in the phenomenon itself of the formavapours of such solutions being always tion of vapour. less elastic than that of pure water, at During these series of experiments, the same temperature.
M. Rudberg examined many times the “ All physiciens appear to hold on the temperature of the vapour of distilled temperature of vapour, the opinions water, principally with the intention of we have just expressed,” says M. Rud- ascertaining if, by the effect of conberg, and he quotes to support this tinued heat, the point of ebullition assertion, several passages from the of the thermometer did not undergo a small change of place. This point was New Term in Physics. raised, in fact, 0.054 Fahr., and subsequently remained at this height. It is now well ascertained that certain
The liquids which were submitted to bodies, organic or inorganic, simple or experiment were solutions of muriate of compound, when in contact, mutually lime, of neutralized carbonate of potash, act on each other in a manner distinct of saltpetre, of common salt, and of sul from simple chemical agency, and that phate of zinc. At the commencement of compounds are the result, the elements each series of experiments, the solutions of which are not immediately traceable were so concentrated that there remained, in the original substances. In the at the temperature of the chamber, organic world, the effects of this unmuch salt undissolved: by boiling the known power are numerous and well solutions again from time to time, they known in the various animal and vege. were gradually still more concentrated. table secretions, and the branch of The conclusion drawn from the experi. science which analyzes the products and ments was, that the vapour which rises their apparent origin has been hence from a saline solution in ebullition has called organic chemistry. In our preprecisely the same temperature as that sent state of ignorance of the subject, which is disengaged from distilled M. Berzelius proposes to give the name water under the same atmospheric catalytic to this unknown agency, and pressure, whatever be the number of catalysis to the decomposition of the degrees which the temperature of the bodies resulting from it." The apparent solution
may be still more elevated by secretion (if we may apply the term reason of the quantity and the nature here) of minerals in veins of rocks, not of the salt dissolved.
apparently containing the immediate Such is the first consequence, to which elements of these depositions, is the the results of these experiments have most remarkable example of the effects led M. Rudberg, in the most satisfac- of catalytic force in the inorganic world; tory manner. Other important ones the recent researches of Mr. Fox, as exseem also to flow from them, but these plained by him at the Bristol British have not yet been established beyond Association meeting, seem to promise doubt by direct experiment.
to throw some additional light on the If we now consider the formation of subject. vapours in saline solutions by evaporation, the experiments of MM. Dalton, Comparison of distant simultaneous Gay-Lussac, and Prinsep, have esta- Vibrations of the Magnetic Needle. blished that the vapour of a saline solution has an elasticity much less HRR. Gauss, Astronomical Professor than that of pure water, when the two in the University of Göttingen, has deliquids have the same temperature. It lineated upon a chart, the variations of therefore follows, inversely, that for the the magnetic needle, as they were same elasticity, the vapour of a saline observed, on the 1st of April, 1835, in solution is hotter than that of pure the cities of Copenhagen, Altona, Götwater. It results likewise from experi- tingen, Leipsic, and Rome*. The viment, that this difference of temperature brations are represented by circular arcs increases with the quantity of salt dis- drawn to the same scale. These arcs solved, and that it also varies according were found to be the longest at Copento the nature of the salt. From these hagen, and the shortest at Rome. The two results it clearly follows that between result is peculiarly deserving of atten. the temperature of vapour and its elas- tion, as the day of observation happened ticity, the relation is sensibly different, to be one on which an eruption of Veaccording as the vapour is produced by suvius occurred. The comparatively the ebullition of a saline solution or by feeble oscillations at Rome at such a evaporation from its surface.
time, would seem to contradict the The cause of this difference, and that opinion grounded upon some other obof the uniformity of the temperature of servations,—that this kind of phevapour formed by water and by saline nomenon has an influence on the magsolutions, under the same atmospheric netic needle. pressure, can only be finally ascertained by a more exact examination of the
Selected, it is presumed, from their difformation of vapours in saline solutions fering little in longitude. by evaporation.