LXXI.-On the Culture of the Begonia. By the EDITOR. It is now three years since the Editor had a present made him, in the beginning of winter, by a friend, of a single tuber of the Begonia, with instructions to plant it, and to keep it dry all the winter; and not to begin to water it in the spring until it began to manifest signs of vegetation, by throwing up shoots through the surface of the soil. He accordingly did so; and in the succeeding year, it grew and throve apace; and, at the latter end of the year, produced its beautiful pale red flowers, with bright yellow globular tufts of apices. Still no female flowers appeared; but, nevertheless, it produced tubers at every joint; and, on the first frosts attacking it, it fell to pieces, and the tubers separated of themselves.

He did not transplant it, but kept it dry all the winter in the flower-pot, in one of the apartments of his house; and, on the shoots appearing in the spring, he began to water it, still without transplanting it, or even adding any manure to the soil; as he thought that the rotted fibres of the last year's roots might prove sufficient to afford nutriment to the plant, and so it turned out. It throve exceedingly, flowered, and again threw off a crop of tubers on the approach of winter. He again suffered it to remain undisturbed in the pot, kept it dry all the winter, and it has just now pushed out numerous stems and leaves through the soil, and promises to flourish luxuriantly in the ensuing summer. It is now two years since the Editor planted two or three of his first crop of tubers, in the soil contained in a garden pot, and which soon vegetated, and produced fine plants, even flowering and producing other tubers in the course of the year; he managed these in a similar manner to the first; and he has now a third pot of young plants, the produce of last year's tubers; and which, indeed, from all the plants, amounted to upwards of a hundred, so readily is this beautiful plant propagated.

He was this year enabled to afford several of his friends

tubers of last year's growth, and which, at their usual period, had thrown out small pink coloured shoots; and, no doubt, by following these very easy instructions, they will be enabled to succeed in the culture of this beautiful plant, as well as the Editor.

Not having hitherto transplanted any of his plants; he has not availed himself of the great increase by the roots or tubers, produced beneath the soil, which is the usual mode of propagating them. He is not aware whether the gardeners in the vicinity of the metropolis have also planted the tubers produced from the stems; but it is evidently a rapid mode of increasing the number of their plants.

LIST OF PATENTS FOR NEW INVENTIONS, Which have passed the Great Seal since March 30, 1830, To John Rawe, Junior, of Albany-street, Regent's-park, in the county of Middlesex, being one of the people called quakers; and John Boase, of the same place, gentleman; for certain improvements in steam-boilers, and a mode of quickening the draught for furnaces connected with the same. Dated March, 30, 1830.-To be specified in six months.

To William Aikin, of Carron Vale, in that part of our United Kingdom called Scotland, esquire; for certain improvements in keeping or preserving beer, ale, and other fermented liquors. Dated March 13, 1830.-In six months.

To Daniel Towers Shears, of Bankside, in the borough of Southwark, in the county of Surrey, coppersmith,; for certain additions to and improvements in the apparatus used in distilling, and also in the process of distilling and rectifying. Dated March 31, 1830.

In two months.

To James Collier, of Newman-street, in the parish of Saint Marylebone, in the county of Middlesex, civil engineer; and Henry Pinkus, of Thayer-street, Manchester-square, in the same parish, gentleman; for an improved method and apparatus, for generating gas for illumination. Dated April 5, 1830.-In six months.

To William Alltoft Summers, of Saint Georges in the East, in the county of Middlesex, engineer; and Nathaniel Ogle, of Mil'brook, in the county of Hants, esquire; for certain improvements in the construction of steam engine and other boilers, or generators, applicable to propelling vessels, locomotive carriages, and other purposes. Dated April 13, 1830.-In six months.

GILL'S

TECHNOLOGICAL & MICROSCOPIC

REPOSITORY.

LXXII.-On the Microscope. By THOMAS CARPENTER, Esq. With Additions by the EDITOR.

SIR,

(Continued from page 318.)

WITH A PLATE.

Tottenham, May 10, 1830.

In the third volume of your Technological Repository, page 272, is contained a brief statement, which I furnished you with, of the devastations committed on various species of property, by the white ants. Alarming as these depredations appear, yet they fall infinitely short of the dangerous ravages made on the timbers of ships, &c., by various species of sea-worms. I herewith send you several portions of ship timber, which has been perforated by one particular species, teredo navalis; you will observe among the whole number of pieces that every part of the interior has been excavated by these animals. I wish to direct your attention to one of the pieces in particular, it being part of the false keel of a ship. The whole of the keel was perforated throughout in a similar manner to this piece. You will observe numerous minute openings on the under side, which were made by the animals whilst in their young state, in order to work their way into the interior; and, as they increased in size, they enlarged or scooped out their dwellings; the wood which they thus scooped out, serving them as food. They are also provided with two singular organs, by one of which they draw through the

VOL. VI.

Y

holes they made at their entrance into the timber, the seawater, in which they find animalcule which serve as their nourishment; the other organ is used by the animal to convey away the waste fluid through their intestinal canal, and which fluid carries off with it the portions of the wood, after the animals have extracted those virtues from it which are necessary for their sustenance.

This destructive animal is in general, when full grown, from four to six inches in length, of a grey colour, and about the thickness of the middle finger. It is covered with a very thin cylindrical and smooth shell, and has two calcareous hemispherical jaws, flat before, and angular behind. Great numbers of these worms, which are supposed to have been introduced from India into Europe, are, as before observed, found in the sides and bottoms of ships, so much so, indeed, as often to endanger them! It is said that our vessels never suffered from these enemies till within the last century, and that we imported them from the sea about the Antilles.

In the year 1730, the inhabitants of the United Provinces were under serious alarm concerning these worms, which had made dreadful depredations in the piles that support the banks of many parts of those coasts. One of the persons who had the care of the Dutch coasts at that time, observed, to his astonishment, that some of the timbers were, in the course only of a few months, made so full of holes, that they could be beaten in pieces with the least force.

The perforations, when the mud was scraped off, did not appear much larger than to admit a pin's head to be thrust into them. A very thin piece of whalebone being put into one of these, would enter straight forward for three or four lines, and the holes then generally for some distance farther proceeded upwards. One of the piles being split lengthwise with a hatchet or wedge, was found full of passages, or hollow cylindrical ducts, each of which contained a worm, enclosed in a kind of testaceous tube or covering, of

a white colour, which it exactly filled, but in such a manner as to be able to move with freedom. This tube was found straight or bent, according to the form of that part of the hole where the animal was employed. The holes at the outer surface were very narrow, but increased in width within, evidently as the worm increased in size. They were never found to run into each other, but all to proceed separately. It was happily discovered, a few years afterwards. that these creatures had totally abandoned these coasts. Thus a contemptible worm, multiplying beyond its usual limits, is capable of destroying the most boasted efforts of human industry! No contrivance has yet been suggested by human ingenuity that has been found fully sufficient to prevent the formidable ravages of these animals.

When Professor Thunberg was in Japan, he observed the manner in which the Japanese contrived to preserve their vessels against the ravages of this destructive worm. This was, simply to drag them on the strand, and burn the sides of them as high as the water usually reached, till they were well covered with a coat of charcoal.

The head of this creature is well prepared for the office of boring, being coated with a strong armour, and furnished with two sharp instruments, by means of which it scoops out the wood. The neck is provided also with muscles of great strength. It is very minute when it first issues from the egg; but, as before observed, grows to the length of near six inches. This tribe of animals generally act gregariously, and take especial care not to interfere with each other's cells or habitations; externally, the opening is scarce visible; but when they have committed their depredations, on taking off a layer of the plank, the whole interior exhibits a honeycomb-appearance, and is generally entirely destroyed. In some sense, this tribe may be said to co-operate at sea with the labours of the termes fatali, or white ants, on land. While, however, it commits enormous mischief on the labours of the shipwright, it also effectually removes those obstructions in rivers, and even in