Part 28

The demand for Sea-water to supply the Marine Aquarium--now to be seen in so many houses--induced Mr. Gosse to attempt the manufacture of Sea-water, more especially as the constituents are well known. He accordingly took Scheveitzer’s analysis of Sea-water for his guide. In one thousand grains of sea-water taken off Brighton, it gave: water, 964·744; chloride of sodium, 27·059; chloride of magnesium, 3·666; chloride of potassium, 9·755; bromide of magnesium, 0·29; sulphate of magnesia, 2·295; sulphate of lime, 1·407; carbonate of lime, 0·033: total, 999·998. Omitting the bromide of magnesium, the carbonate of lime, and the sulphate of lime, as being very small quantities, the component parts were reduced to common salt, 3½ oz.; Epsom salts, ¼ oz.; chloride of magnesium, 200 grains troy; chloride of potassium, 40 grains troy; and four quarts of water. Next day the mixture was filtered through a sponge into a glass jar, the bottom covered with shore-pebbles and fragments of stone and fronds of green sea-weed. A coating of green spores was soon deposited on the sides of the glass, and bubbles of oxygen were copiously thrown off every day under the excitement of the sun’s light. In a week Mr. Gosse put in species of _Actinia Bowerbankia_, _Cellularia_, _Serpula_, &c. with some red sea-weeds; and the whole throve well.

VELOCITY OF IMPRESSIONS TRANSMITTED TO THE BRAIN.

Professor Helmholtz of Königsberg has, by the electro-magnetic method,[58] ascertained that the intelligence of an impression made upon the ends of the nerves in communication with the skin is transmitted to the brain with a velocity of about 195 feet per second. Arrived at the brain, about one-tenth of a second passes before the will is able to give the command to the nerves that certain muscles shall execute a certain motion, varying in persons and times. Finally, about 1/100th of a second passes after the receipt of the command before the muscle is in activity. In all, therefore, from the excitation of the sensitive nerves till the moving of the muscle, 1¼ to 2/10ths of a second are consumed. Intelligence from the great toe arrives about 1/30th of a second later than from the ear or the face.

Thus we see that the differences of time in the nervous impressions, which we are accustomed to regard as simultaneous, lie near our perception. We are taught by astronomy that, on account of the time taken to propagate light, we now see what has occurred in the fixed stars years ago; and that, owing to the time required for the transmission of sound, we hear after we see is a matter of daily experience. Happily the distances to be traversed by our sensuous perceptions before they reach the brain are so short that we do not observe their influence, and are therefore unprejudiced in our practical interest. With an ordinary whale the case is perhaps more dubious; for in all probability the animal does not feel a wound near its tail until a second after it has been inflicted, and requires another second to send the command to the tail to defend itself.

PHOTOGRAPHS ON THE RETINA.

The late Rev. Dr. Scoresby explained with much minuteness and skill the varying phenomena which presented themselves to him after gazing intently for some time on strongly-illuminated objects,--as the sun, the moon, a red or orange or yellow wafer on a strongly-contrasted ground, or a dark object seen in a bright field. The doctor explained, upon removing the eyes from the object, the early appearance of the picture or image which had been thus “photographed on the Retina,” with the photochromatic changes which the picture underwent while it still retained its general form and most strongly-marked features; also, how these pictures, when they had almost faded away, could at pleasure, and for a considerable time, be renewed by rapidly opening and shutting the eyes.

DIRECT EXPLORATION OF THE INTERIOR OF THE EYE.

Dr. S. Wood of Cincinnati states, that by means of a small double convex lens of short focus held near the eye,--that organ looking through it at a candle twelve or fifteen feet distant,--there will be perceived a large luminous disc, covered with dark and light spots and dark streaks, which, after a momentary confusion, will settle down into an unchanging picture, which picture is composed of the organs or internal parts of the eye. The eye is thus enabled to view its own internal organisation, to have a beautiful exhibition of the vessels of the cornea, of the distribution of the lachrymas secretions in the act of winking, and to see into the nature and cause of _muscæ volitantes_.

NATURE OF THE CANDLE-FLAME.

M. Volger has subjected this Flame to a new analysis.

He finds that the so-called _flame-bud_, a globular blue flaminule, is first produced at the summit of the wick: this is the result of the combustion of carbonic oxide, hydrogen, and carbon, and is surrounded by a reddish-violet halo, the _veil_. The increased heat now gives rise to the actual flame, which shoots forth from the expanding bud, and is then surrounded at its inferior portion only by the latter. The interior consists of a dark gaseous cone, containing the immediate products of the decomposition of the fatty acids, and surrounded by another dark hollow cone, the _inner cap_. Here we already meet with carbon and hydrogen, which have resulted from the process of decomposition; and we distinguish this cone from the inner one by its yielding soot. The _external cap_ constitutes the most luminous portion of the flame, in which the hydrogen is consumed and the carbon rendered incandescent. The surrounding portion is but slightly luminous, deposits no soot, and in it the carbon and hydrogen are consumed.--_Liebig’s Annual Report._

HOW SOON A CORPSE DECAYS.

Mr. Lewis, of the General Board of Health, from his examination of the contents of nearly 100 coffins in the vaults and catacombs of London churches, concludes that the complete decomposition of a corpse, and its resolution into its ultimate elements, takes place in a leaden coffin with extreme slowness. In a wooden coffin the remains, with the exception of the bones, vanish in from two to five years. This period depends upon the quality of the wood, and the free access of air to the coffins. But in leaden coffins, 50, 60, 80, and even 100 years are required to accomplish this. “I have opened,” says Mr. Lewis, “a coffin in which the corpse had been placed for nearly a century; and the ammoniacal gas formed dense white fumes when brought in contact with hydrochloric-acid gas, and was so powerful that the head could not remain in it for more than a few seconds at a time.” To render the human body perfectly inert after death, it should be placed in a light wooden coffin, in a pervious soil, from five to eight feet deep.

MUSKET-BALLS FOUND IN IVORY.

The Ceylon sportsman, in shooting elephants, aims at a spot just above the proboscis. If he fires a little too low, the ball passes into the tusk-socket, causing great pain to the animal, but not endangering its life; and it is immediately surrounded by osteo-dentine. It has often been a matter of wonder how such bodies should become completely imbedded in the substance of the tusk, sometimes without any visible aperture; or how leaden bullets become lodged in the solid centre of a very large tusk without having been flattened, as they are found by the ivory-turner.

The explanation is as follows: A musket-ball aimed at the head of an elephant may penetrate the thin bony socket and the thinner ivory parietes of the wide conical pulp-cavity occupying the inserted base of the tusk; if the projectile force be there spent, the ball will gravitate to the opposite and lower side of the pulp-cavity. The pulp becomes inflamed, irregular calcification ensues, and osteo-dentine is formed around the ball. The pulp then resumes its healthy state and functions, and coats the osteo-dentine enclosing the ball, together with the root of the conical cavity into which the mass projects, with layers of normal ivory. The hole formed by the ball is soon replaced, and filled up by osteo-dentine, and coated with cement. Meanwhile, by the continued progress of growth, the enclosed ball is pushed forward to the middle of the solid tusk; or if the elephant be young, the ball may be carried forward by growth and wear of the tusk until its base has become the apex, and become finally exposed and discharged by the continual abrasion to which the apex of the tusk is subjected.--_Professor Owen._

NATURE OF THE SUN.

To the article at pp. 59-60 should be added the result obtained by Dr. Woods of Parsonstown, and communicated to the _Philosophical Magazine_ for July 1854. Dr. Woods, from photographic experiment, has no doubt that the light from the centre of flame acts more energetically than that from the edge on a surface capable of receiving its impression; and that light from a luminous solid body acts equally powerfully from its centre or its edges: wherefore Dr. Woods concludes that, as the sun affects a sensitive plate similarly with flame, it is probable its light-producing portion is of a similar nature.

_Note to_ “IS THE HEAT OF THE SUN DECREASING?” _at page 65_.--Dr. Vaughan of Cincinnati has stated to the British Association: “From a comparison of the relative intensity of solar, lunar, and artificial light, as determined by Euler and Wollaston, it appears that the rays of the sun have an illuminating power equal to that of 14,000 candles at a distance of one foot, or of 3500,000000,000000,000000,000000 candles at a distance of 95,000,000 miles. It follows that the amount of light which flows from the solar orb could be scarcely produced by the daily combustion of 200 globes of tallow, each equal to the earth in magnitude. A sphere of combustible matter much larger than the sun itself should be consumed every ten years in maintaining its wonderful brilliancy; and its atmosphere, if pure oxygen, would be expended before a few days in supporting so great a conflagration. An illumination on so vast a scale could be kept up only by the inexhaustible magazine of ether disseminated through space, and ever ready to manifest its luciferous properties on large spheres, whose attraction renders it sufficiently dense for the play of chemical affinity. Accordingly suns derive the power of shedding perpetual light, not from their chemical constitution, but from their immense mass and their superior attractive power.”

PLANETOIDS.

+----------------+---------------+-----------+-----------+-----------+ | | | | | No. | | | | | |discovered | | | Date of | | Place of | by each | | Name. | Discovery. |Discoverer.| Discovery.|astronomer.| +----------------+---------------+-----------+-----------+-----------+ |Mercury, Mars, }| Known } | | | | |Venus, Jupiter,}| to the } | ... | ... | -- | |Earth, Saturn, }| ancients.} | | | | | Uranus |1781, March 13 |W. Herschel| Bath | -- | | Neptune[59] |1846, Sept. 23 |Galle | Berlin | -- | | 1 Ceres |1801, Jan. 1 |Piazzi | Palermo | 1 | | 2 Pallas |1802, March 28 |Olbers | Bremen | 1 | | 3 Juno |1804, Sept. 1 |Harding | Lilienthal| 1 | | 4 Vesta |1807, March 29 |Olbers | Bremen | 2 | | 5 Astræa |1845, Dec. 8 |Encke | Driesen | 1 | | 6 Hebe |1847, July 1 |Encke | Driesen | 2 | | 7 Iris |1847, August 13|Hind | London | 1 | | 8 Flora |1847, Oct. 18 |Hind | London | 2 | | 9 Metis |1848, April 25 |Graham | Markree | 1 | |10 Hygeia |1849, April 12 |Gasperis | Naples | 1 | |11 Parthenope |1850, May 11 |Gasperis | Naples | 2 | |12 Victoria |1850, Sept. 13 |Hind | London | 3 | |13 Egeria |1850, Nov. 2 |Gasperis | Naples | 3 | |14 Irene |1851, May 19 |Hind | London | 4 | |15 Eunomia |1851, July 29 |Gasperis | Naples | 4 | |16 Psyche |1852, March 17 |Gasperis | Naples | 5 | |17 Thetis |1852, April 17 |Luther | Bilk | 1 | |18 Melpomene |1852, June 24 |Hind | London | 5 | |19 Fortuna |1852, August 22|Hind | London | 6 | |20 Massilia |1852, Sept. 19 |Gasperis | Naples | 6 | |21 Lutetia |1852, Nov. 15 |Goldschmidt| Paris | 1 | |22 Calliope |1852, Nov. 16 |Hind | London | 7 | |23 Thalia |1852, Dec. 15 |Hind | London | 8 | |24 Themis |1853, April 5 |Gasperis | Naples | 7 | |25 Phocea |1853, April 6 |Chacornac | Marseilles| 1 | |26 Proserpine |1853, May 5 |Luther | Bilk | 2 | |27 Euterpe |1853, Nov. 8 |Hind | London | 9 | |28 Bellona |1854, March 1 |Luther | Bilk | 3 | |29 Amphitrite |1854, March 1 |Marth | London | 1 | |30 Urania |1854, July 22 |Hind | London | 10 | |31 Euphrosyne |1854, Sept. 1 |Furguson | Washington| 1 | |32 Pomona |1854, Oct. 26 |Goldschmidt| Paris | 2 | |33 Polyhymnia |1854, Oct. 28 |Chacornac | Paris | 2 | |34 Circe |1855, April 6 |Chacornac | Paris | 3 | |35 Leucothea |1855, April 19 |Luther | Bilk | 4 | |36 Atalante |1855, Oct. 5 |Goldschmidt| Paris | 3 | |37 Fides |1855, Oct. 5 |Luther | Bilk | 5 | |38 Leda |1856, Jan. 12 |Chacornac | Paris | 4 | |39 Lætitia |1856, Feb. 8 |Chacornac | Paris | 5 | |40 Harmonia |1856, March 31 |Goldschmidt| Paris | 4 | |41 Daphne |1856, May 22 |Goldschmidt| Paris | 5 | |42 Isis |1856, May 23 |Pogson | Oxford | 1 | |43 Ariadne |1857, April 15 |Pogson | Oxford | 2 | |44 Nysa |1857, May 27 |Goldschmidt| Paris | 6 | |45 Eugenia |1857, June 28 |Goldschmidt| Paris | 7 | |46 Hastia |1857, August 16|Pogson | Oxford | 3 | |47 Aglaia |1857, Sept. 15 |Luther | Bilk | 6 | |48 Doris |1857, Sept. 19 |Goldschmidt| Paris | 8 | |49 Pales |1857, Sept. 19 |Goldschmidt| Paris | 9 | |50 Virginia |1857, Oct. 4 |Furguson | Washington| 2 | |51 Nemausa |1858, Jan. 22 |Laurent | Nismes | 1 | |52 Europa |1858, Feb. 6 |Goldschmidt| Paris | 10 | |53 Calypso |1858, April 8 |Luther | Bilk | 7 | |54 Alexandra |1858, Sept. 11 |Goldschmidt| Paris | 11 | |55 (Not named) |1858, Sept. 11 |Searle | Albany | 1 | +----------------+---------------+-----------+-----------+-----------+

THE COMET OF DONATI.

While this sheet was passing through the press, the attention of astronomers, and of the public generally, was drawn to the fact of the above Comet passing (on Oct. 18) within nine millions of miles of the planet Venus, or less than 9/100ths of the earth’s distance from the Sun. “And (says Mr. Hind, the astronomer), it is obvious that if the comet had reached its least distance from the sun a few days earlier than it has done, the planet might have passed through it; and I am very far from thinking that close proximity to a comet of this description would be unattended with danger. The inhabitants of Venus will witness a cometary spectacle far superior to that which has recently attracted so much attention here, inasmuch as the tail will doubtless appear twice as long from that planet as from the earth, and the nucleus proportionally more brilliant.”

This Comet was first discovered by Dr. G. B. Donati, astronomer at the Museum of Florence, on the evening of the 2d of June, in right ascension 141° 18′, and north declination 23° 47′, corresponding to a position near the star Leonis. Previous to this date we had no knowledge of its existence, and therefore it was not a predicted comet; neither is it the one last observed in 1556. At the date of discovery it was distant from the earth 228,000,000 of miles, and was an excessively faint object in the largest telescopes.

The tail, from October 2 to 16, when the comet was most conspicuous, appears to have maintained an average length of at least 40,000,000 miles, subtending an angle varying from 30° to 40°. The dark line or space down the centre, frequently remarked in other great comets, was a striking characteristic in that of Donati. The nucleus, though small, was intensely brilliant in powerful instruments, and for some time bore high magnifiers to much greater advantage than is usual with these objects. In several respects this comet resembled the famous ones of 1744, 1680, and 1811, particularly as regards the signs of violent agitation going on in the vicinity of the nucleus, such as the appearance of luminous jets, spiral offshoots, &c., which rapidly emanated from the planetary point and as quickly lost themselves in the general nebulosity of the head.

On the 5th Oct. the most casual observer had an opportunity of satisfying himself as to the accuracy of the mathematical theory of the motions of comets in the near approach of the nucleus of Donati’s to Arcturus, the principal star in the constellation Bootes. The circumstance of the appulse was very nearly as predicted by Mr. Hind.

The comet, according to the investigations by M. Loewy, of the Observatory of Vienna, arrived at its least distance from the sun a few minutes after eleven o’clock on the morning of the 30th of September; its longitude, as seen from the sun at this time, being 36° 13′, and its distance from him 55,000,000 miles. The longer diameter of its orbit is 184 times that of the earth’s, or 35,100,000,000 miles; yet this is considerably less than 1/1000th of the distance of the nearest fixed star. As an illustration, let any one take a half-sheet of note-paper, and marking a circle with a sixpence in one corner of it, describe therein our solar system, drawing the orbits of the earth and the inferior planets as small as he can by the aid of a magnifying-glass. If the circumference of the sixpence stands for the orbit of Neptune, then an oval filling the page will fairly represent the orbit of Donati’s comet; and if the paper be laid upon the pavement under the west door of St. Paul’s Cathedral, London, the length of that edifice will inadequately represent the distance of the nearest fixed star. The time of revolution resulting from Mr. Loewy’s calculations is 2495 years, which is about 500 years less than that of the comet of 1811 during the period it was visible from the earth.

That the comet should take more than 2000 years to travel round the above page of note-paper is explained by its great diminution of speed as it recedes from the sun. At its perihelion it travelled at the rate of 127,000 miles an hour, or more than twice as fast as the earth, whose motion is about 1000 miles a minute. At its aphelion, however, or its greatest distance from the sun, the comet is a very slow body, sailing at the rate of 480 miles an hour, or only eight times the speed of a railway express. At this pace, were it to travel onward in a straight line, the lapse of a million of years would find it still travelling half way between our sun and the nearest fixed star.

As this comet last visited us between 2000 and 2495 years since, we know that its appearance was at an interesting period of the world’s history. It might have terrified the Athenians into accepting the bloody code of Draco. It might have announced the destruction of Nineveh, or of Babylon, or the capture of Jerusalem by Nebuchadnezzar. It might have been seen by the expedition which sailed round Africa in the reign of Pharaoh Necho. It might have given interest to the foundation of the Pythian games. Within the probable range of its last visitation are comprehended the whole of the great events of the history of Greece; and among the spectators of the comet may have been the so-called sages of Greece and even the prophets of Holy Writ: Thales might have attempted to calculate its return, and Jeremiah might have tried to read its warning.--_Abridged from a Communication from Mr. Hind to the Times, and from a Leader in that Journal._

FOOTNOTES:

[1] From a photograph, with figures, to show the relative size of the tube aperture.

[2] Weld’s _History of the Royal Society_, vol. ii. p. 188.

[3] Dr. Whewell (_Bridgewater Treatise_, p. 266) well observes, that Boyle and Pascal are to hydrostatics what Galileo is to mechanics, and Copernicus, Kepler, and Newton are to astronomy.

[4] The Rev. Mr. Turnor recollects that Mr. Jones, the tutor, mentioned, in one of his lectures on optics, that the reflecting telescope belonging to Newton was then lodged in the observatory over the gateway; and Mr. Turnor thinks that he once saw it, with a finder affixed to it.

[5] The story of the dog “Diamond” having caused the burning of certain papers is laid in London, and in Newton’s later years. In the notes to Maude’s _Wenleysdale_, a person then living (1780) relates, that Sir Isaac being called out of his study to a contiguous room, a little dog, called Diamond, the constant but incurious attendant of his master’s researches, happened to be left among the papers, and by a fatality not to be retrieved, as it was in the latter part of Sir Isaac’s days, threw down a lighted candle, which consumed the almost finished labour of some years. Sir Isaac returning too late but to behold the dreadful wreck, rebuked the author of it with an exclamation (_ad sidera palmas_), “O Diamond! Diamond! thou little knowest the mischief done!” without adding a single stripe. M. Biot gives this fiction as a true story, which happened some years after the publication of the _Principia_; and he characterises the accident as having deprived the sciences forever of the fruit of so much of Newton’s labours.--Brewster’s _Life_, vol. ii. p. 139, note. Dr. Newton remarks, that Sir Isaac never had any communion with dogs or cats; and Sir David Brewster adds, that the view which M. Biot has taken of the idle story of the dog Diamond, charged with fire-raising among Newton’s manuscripts, and of the influence of this accident upon the mind of their author, is utterly incomprehensible. The fiction, however, was turned to account in giving colour to M. Biot’s misrepresentation.

[6] Bohn’s edition.