cient dame, even in these days of enlightenment, are thus described by Mr. Carpenter:-This singular noise proceeds from two different insects. One of these, the Anòbium tessellatum, is coleopterous, of a dark colour, and about a quarter of an inch in length. It is chiefly in the latter end of spring it commences its noise, which may be considered analogous to the call of birds. This is caused by beating on hard substances, with the shield or fore-part of its head. The general number of successive distinct strokes is from seven to nine, or eleven. These are given in pretty quick succession, and are repeated at uncertain intervals. In old houses, where the insects are numerous, they may be heard, if the weather be warm, almost every hour in the day. In beating, the insect raises itself upon its hinder legs, and, with the body somewhat inclined, beats its head, with great force and agility, against the place on which it stands. This insect, which is the real death-watch of the vulgar, must not be confounded with a minuter insect, not much unlike a louse, which makes a ticking noise like a watch; but, instead of beating at intervals, it continues its noise for a considerable length of time without intermission. This latter insect, the Térmes pulsatòrium Linn., belongs to a very different tribe (Neuróptera). It is usually found in old wood, decayed furniture, museums, and neglected books. The female lays her eggs, which are exceedingly small, in dry dusty places, where they are likely to meet with least disturbance. They are generally hatched about the beginning of March, a little sooner or later, according to the weather. After leaving the eggs, the insects are so small as scarcely to be discerned without the use of a glass. They remain in this larva state about two months, somewhat resembling in appearance the mites in cheese; after which they undergo their change into the perfect insect. They feed on dead flies and other insects; and often, from their numbers and voracity, very much deface cabinets of natural history. They subsist on various other substances, and may often be observed carefully hunting for nutritious particles amongst the dust in which they are found, turning it over with their heads, and searching about somewhat in the manner of swine. Many live through the winter, buried deep in the dust, to avoid the frost. (Gill's Technological and Microscopical Repository.)

British Pearls (Mya margaritifera Linn., U`nio elongata Lam. (fig. 112.) -In the old and curious translation of Hector Boetius, by Bellenden (edit. Edinb. 1541), the

following notice occurs of British pearls:-" In the horse mussillis are generit perlis.

Thir mussillis airlie in the morning (when the lift is cleir and temperate), openis thair mouthis a little aboue the watter, and maist gredelie

swellis the dew of

heaven, and eftir the measure of the dew thay swellie, they conceive and bredis the perle."

Suetonius gives, as one reason for Cæsar's expedition into Britain, the search for pearls, which Pliny (Hist. Nat., ix. 35.) seems to confirm, saying that Julius Cæsar gave a breastplate covered with British pearls to Venus Genetrix, and hung it in her temple at Rome. Pliny adds, that they were small and ill-coloured; and Tacitus says, "subfusca ac liventia." The

venerable Bede, again, in his Ecclesiastical History, says, the British pearls were excellent, and of all colours, reddish, pale, violet, and green, which account is confirmed by Origen. Not many years ago, a patent was granted to fish for pearls in the river Jut, in Cumberland (Gibson in Camden's Britannia), but it does not appear to have been much acted upon.-J. Rennie.

ART. III. Botany.

CHANGES made in the Names of Plants. — I cannot help producing a few instances, from amongst a very large number, where the alterations appear to me to be decided improvements. I say nothing respecting generic terms, but have confined myself to the trivial or specific name: - Fritillaria meleàgris of Linnæus, Mr. Salisbury proposes to change to F. tessellata; Hippóphae rhamnöìdes to H. littoralis; and Campanula Trachèlium to C. urticifolia, all certainly changes for the better. Who will not prefer, if he thinks for a moment, Verónica fontinàlis and bibarbàta (one expressing the place of growth, and the other alluding to the situation of the hairs on the stem) to the barbarously sounding words Beccabúnga and Chama`drys, to which few are able to attach any meaning? And is not Gerard's name of the common Scurvy-Grass, Cochleària rotundifòlia, expressive of the form of the leaf, better than C. officinalis? I think it highly objectionable to continue the name officinàlis to so many plants merely because they have been used medicinally, and shall be glad to see some one take up the subject, and "reform it altogether." (See Gray's Nat. Arrangement of Brit. Plants.)— D. S. Bungay.

Preservation of Trees in Winter. · - In iron founderies, such as the foundery for cannon at Munich, it is customary to stir the melted metal with a branch of green oak; and notwithstanding the great heat of the metal, the green wood is not affected deeper than about the twentieth part of an inch. This striking fact is explained from the non-conducting power of the sap; and upon the same principle it is that the bodies and branches of trees, not having the covering of snow which the roots have, are protected from the operation of cold by their sap increasing in spissitude, and, of course, in non-conducting capacity, as the winter approaches. On similar principles we may account for the preservation of various kinds of fruits.-J. R.

Sap of the Rose Tree.-From a plant of Ròsa rubiflòra, at Hammersmith, with a stem 3 ft. high and 24 in. in diameter, when deprived of its branches and the head sawed off, 29th of July, 31 ounces of sap flowed in about a week, which, together with loss by evaporation, probably exceeded three pints. Chemical analysis gave the following ingredients:

be

With respect to what Mr. Adams chooses to call extractive, I may permitted to remark that the term ought to be exploded altogether from vegetable chemistry, since it does not, like the terms gum, acid, or alkali,

*

convey any distinct meaning, nor apply to a definite class of substances. The recent brilliant discoveries in vegetable chemistry ought to put an end to this vague phraseology.-J. R.

Influence of Soil on Roots. "If a cucumber," says Sir James Smith in his Lectures, of which MS. notes are now before me, "is planted; and after the branches shoot there is placed a stone in the way of either of them, the branch will turn off and avoid it without touching the stone, but describing a circle around it. When it has passed the stone, however, it will go on in a straight line." Sir James explains this by the well-known law of plants always approaching the light, the cucumber turning round to get out of the shadow of the stone.

Roots follow a very different law, always endeavouring to get away from the light; and, accordingly, so far from avoiding a stone or other obstacle, they often cling closely around it, and sometimes even mould their forms upon the hard substances with which they meet. This is well exemplified in the root of an alder tree Alnus glutinòsa, Bétula A'lnus Linn.), which my little boy found in his searches after fresh-water shells for his collection. (SeeVol.I. p. 413.) The root (fig. 113 a) was embedded among the gravel formed by theRavensbourne river which passes the bottom of my garden; and it requires no details to point out how exactly it has moulded itself on every stone which it met with in its course. In the same manner roots are much influenced in their forms by the soils in which they grow. Of this I lately gave the following illustration in the Athenæum, from the familiar instance of fibrous and bulbous roots: - When plants with fibrous roots are placed in certain situations, they are apt to change their fibrous structure for a bulbous one, in the same way as the water crowfoot (Ranúnculus aquátilis) has scolloped leaves above, and minutely winged leaves below, water. The change from fibrous to bulbous roots, and the contrary, is markedly exemplified in some of the grasses, particularly in Ti

mothy grass (Phleum) and fox-tail grass (Alopecurus). Before this change of form was discovered, botanists frequently described the same grass under different names; a circumstance which occurred with regard to Alopecurus geniculatus (b) and Phleum pratense (c). Leers seems to have been the first to discover that transplanting into a light rich soil tends to change the bulbous into the fibrous structure.-J. Rennie.

Descent of the Radicles in the Germination of Seeds.-The unsatisfactory nature of several of the theories hitherto proposed on this subject has been ably shown by H. Johnson, Esq., in a paper read before the Medical Society * This was y case with if root of HH 4 the Horseradish in digging. a well for a Privy in my Estate at downham & found it had gone down ten fiet piercing thro'de bed of sex go into jina jarid; that part of y root which had passed to rooga was bent, sivister, and digged like the great, and 16bit portion is fastelen. was rely shaight, without a lind, and rerfectly u coulcher

of Edinburgh, and published in Jamieson's Journal for April. According to Dr. Darwin the radicle is stimulated by moisture, and elongates itself where it is most excited; according to Mr. Knight the radicle obeys the laws of gravitation. Mr. Johnson found that the radicle could be made to grow either downwards or upwards, according to the seed's being placed on the upper or the under surface of a mass of moistened earth, a result with which the experience of every gardener renders him familiar. Had Dr. Darwin, instead of the word moisture, used the term moist soil, his theory would have been unanswerable; as it stands, it is still by far the nearest to the truth. The fallacy of Mr. Knight's theory, which was adopted by Sir Humphry Davy in the earlier editions of his Agricultural Chemistry, is rendered sufficiently obvious by Mr. Johnson's experiments; but it had ceased to be in repute for a number of years Mr. Johnson agrees with Dr. Thompson and M. Aubert Du Petit-Thouars in ascribing this power of the vegetable to the vital principle. — Cond.

:

The Sun-Flower. - I was somewhat surprised to find the following passage in Drummond's First Steps to Botany, an excellent little work: "Leaves always turn to the light, and some flowers regularly follow the sun, facing him when he rises, and also when he sets. It is strange that the sun-flower is so generally supposed to possess this property, since the slightest observation is sufficient to prove its fallacy. Gerarde detected the error so long ago as 1597." He then quotes the passage from Gerarde's Herbal, p. 614., in support of the above assertion, wherein Gerarde says, he could never observe the property, although he had endeavoured to find out the truth of it. Last year I had fifteen sun-flowers in my little garden, and it was a constant source of amusement to observe the flowers following so regularly as they did the course of the sun. In the evening when we retired they all looked towards the setting sun, but in the morning all were turned the contrary way, to be ready to meet the first beams of the great luminary of the day; and this continued daily until the flowers faded, and the work of fructification was over, when the sensibility to the light seemed to be lost, and the head remained fixed. The popular reason for the name of the flower is this very property, and it is rather unaccountable how it should have escaped the notice of Dr. Drummond.

Since I wrote the above I found the following passage in Smith's Introduction to Botany, p. 159. ed. 4. :-" Nor is the effect of light peculiar to leaves alone. Many flowers are equally sensible to it, especially the compound radiated ones, as the daisy, sun-flower, marigold, &c. The stately annual sun-flower, Helianthus annuus, displays this phenomenon more conspicuously on account of its size, but many of the tribe have greater sensibility to light. Its stem is compressed, in some degree, to facilitate the movement of the flower, which, after following the sun all day, returns after sun-set to the east, by its natural elasticity to meet his beams in the morning. Dr. Hales thought the heat of the sun, by contracting the stem on one side, occasioned the flower to incline that way; but if so, it could scarcely return completely at night. There can be no doubt, from the observation of other similar flowers, that the impression is made on their radiated florets, which act as wings, and seem contrived chiefly for that purpose, being frequently destitute of any other use." How is this difference in the two authors to be accounted for? - D. Stock. Bungay, July 28. 1828. Sloughing of Plants.- The power of sloughing has been denied to plants without good reason; for at a certain time of the year the leaves of a plant decay and fall off: so do ripe fruit. If a shrub, when in leaf, be planted, and any part of it die, the leaves formerly expanded will adhere to it, but those on the living branches will wither, fall off, and give place to others. -(MS Lectures of Sir J. E. Smith.)

ART. IV. Geology.

Sir, In common with

MISTATEMENTS in Ure's New System of Geology. every lover of natural history, I hailed the first appearance of your periodical with pleasure; and the gratification has been increased by every suc cessive Number, so admirably is it calculated to promote the objects for which it was designed. I live in a remote part of the country, and can indulge my favourite pursuits but partially, not being within reach of any scientific library, and not having the means to purchase the works on science which I require. I am, therefore, obliged to economise, and be guided in my purchase by the opinions of the reviews in respectable journals. I know so little of geology, and yet feel so deeply interested in that science, from the novel and extraordinary facts which your Magazine and other works have from time to time noticed, that I had put by my little pittance to purchase an elementary work on the subject; and seeing in Brande's Journal, and other periodicals, a very high eulogium passed on Dr. Ure's" New System of Geology, in which the great Revolutions of the Earth and animated Nature are reconciled at once to Modern Science and Sacred History," I was induced to send my guinea to the bookseller, and procured the volume so much praised by those who must certainly have been capable of judging, and which was ushered into the world with such high pretensions. Now, Sir, I do not profess to be even a tyro in geology, but I am acquainted with a few facts, which (if I am not greatly mistaken) are sadly distorted and misrepresented in the work alluded to. I will but briefly notice a few instances of what appear to me to be errors, convinced that, if I am correct, you will think it your duty to guard your readers against a system which is likely to be the more injurious to the science of geology, since it emanates from so respectable a quarter, and has been praised by such high authority. You must indeed, Mr. Editor, allow me to remark, that it is as much your duty to guard your readers against erroneous publications, as it is to point out the most valuable ones to their notice. I have neither the time, inclination, nor ability to attempt a review of such a work as Dr. Ure's: I merely wish to notice some of its more glaring errors; and, if my remarks are incorrect, shall be most happy to be set right, and offer all due apology for my presumption. The first error (and it is an important one) that strikes me is in the Table of Equivalents (pp. 136, 137.), in which the LIAS is placed above the coral rag, cornbrash, Bath oolite, &c., and immediately beneath the " green sand!" The " green sand" comes next to the lias, and the craie inférieuse of the French is named as the equivalent. Where, then, should the Hastings' beds and the Purbeck be placed? for the chalk is next in order. In this instance, as in another hereafter noticed, Dr. Ure seems to have forgotten that the sands and clays, below the green sand of the chalk, form, together with the Purbeck, a well-characterised fresh-water formation, separating the chalk from the oolite.

At pp. 272, 273. the acknowledged imperfect account of the beds between the chalk and oolite, given in Messrs. Conybeare and Phillip's work, is inserted almost verbatim; Dr. Ure, as in the instance above quoted, losing sight of the discoveries which the researches of later geologists have brought to light. Accordingly, he enumerates the strata as, 1. Iron sand; 2. Interjacent clay, or Weald clay; 3. Green sand; 4. Chalk marl; and adds, " all these strata are probably of marine origin:" and, in noticing the "iron sand (p. 274.), he remarks, "the organic remains of this bed have been imperfectly explored: they are not numerous; but the Naútilus, Belemnites, Ammonites, O'streæ, Terrebrátulæ, and spines of an Echìnus cídaris have been found." Now, Sir, I would respectfully submit, that all this is palpably wrong; and how Dr. Ure, with Mr. Mantell's work on the fossils of the Hastings' bed before him (and which he repeatedly quotes in his