were always at a certain distance from them, the inclination of the needle would be always the same at equal distances from the equator, and might be very useful for determining the latitudes. But it would seem, that these poles are perpetually shifting their places, since both the inclination and horizontal direction of the needle are continually varying even in the same place: so that its quantity of inclination cannot be exactly calculated. Two general remarks may be made upon this subject. 1. That the inclination of the needle does not alter regularly in going from N. to S. or from S. to N. in any meridian. 2. That its alteration in the same place, and at different times, is but small. Thus, in London, about the year 1576, the dip was 70° 50′ below the horizon, and in 1775 it stood at 72° 3′; the alteration in nearly 200 years, scarce amounting to three quarters of a degree, which may be attributed to the errors of the instruments; as these were at first exceedingly erroneous, and even yet are far from being perfect.

The general method of constructing dipping needles is, to pass an axis quite through the needle itself, and to let the extremities of the axis rest upon two supports, like the beam of a pair of scales, that the needle may move vertically round; and hence, when placed in the magnetic meridian, it will naturally assume that position which is called the magnetic line, viz. the two ends nearly north and south, and one of them inclined considerably to the horizon. The degrees of this inclination are shown upon a graduated circle; and when the instrument is made use of at land it has a stand, but at sea a ring is necessary to suspend it. When furnished with a stand, it has also a spirit-level; and the stand has three screws, by which the whole is adjusted in such a manner as to let the centre of motion in the needle, and the mark of 90° on the lower part of the divided circle, be exactly in the same line perpendicular to the horizon. The greatest imperfections attending this instrument are the balancing of the needle itself, and the difficulty of knowing whether, after being made magnetic, it be properly balanced or not. The inaccuracy here indeed can be but very small, as arising only from dust or moisture. The method recommended by Mr. Cavallo, to obviate these inconveniences, is first to observe the dip of the needle, then to reverse its magnetism by the application of magnets, so that the end of it which before was elevated above the horizon may now be below it; and, lastly, to observe its dip again; for a mean of the two observations will be pretty near the truth, though the needle may not be perfectly balanced. See MAGNETISM, and MAGNETICAL NEEDLE.

In order to determine the law that regulates the inclination or dip of the needle, Biot, in a memoir delivered by himself and Humboldt to the French National Institute, on the Variations of the Terrestrial Magnetism in different Latitudes, supposed in the axis of the magnetic equator, and at equal distances from the centre of the earth, two centres of attractive forces, the one austral and the other boreal, so as to represent the two opposite magnetic poles of the earth: he then calculated the

effect which ought to result from the action of these centres upon any point of the earth's surface, assuming the attractive force in the reciprocal ratio of the squares of the distances; he found that his results approximated more and more to the truth in proportion as the distance between the magnetic poles was assumed less; and, indeed, by supposing those two poles or centres to coincide, or the inclination of the magnetic needle to be produced by an indefinitely small magnet placed in the centre of the earth, his theorem gave the same numbers as had been observed by Humboidt both in Europe and in America, as well as what had been observed in Russia, Lapland, and various other places in both hemispheres: the results of theory being classed with those of observations in a comparative table, which clearly evinces their near coincidence. Let u be the angle included between a radius drawn from the earth's centre to any assumed point on its surface and the magnetic axis, ß, the angle comprehended between the line coinciding with the real position of the needle and the said magnetic axis, and I the inclination of the needle with the horizon of the place; then we have

I 90° + u — B.

Still it must be observed, that though these formulæ, given by Biot, furnished in general results very near the truth; yet when he attempted to represent the inclinations in different latitudes by the supposition of a magnet infinitely small, very near the centre of the earth, and perpendicular to the magnetic equator, he did not pretend to consider the hypothesis as any thing real, but solely as a mathematical abstraction.

DIPSACUS, teasel, in botany, a genus of the monogynia order, and tetrandria class of plants: CAL. is polyphillous, proper above; the receptacle paleaceous. There are four species: the most remarkable is the D. carduus fullonum, which grows wild in many parts of England. It is of singular use in raising the knap upon woollen cloth. For this purpose the heads are fixed round the circumference of a large broad wheel, which is made to turn round, and the cloth is held against them. In the west of England, great quantities of the plant are cultivated for this use. It is propagated by sowing the seeds in March, upon a well prepared soil. About one peck of seed is sufficient for an acre, as the plants must have room to grow; otherwise the heads will not be large enough, nor in great quantity. When the plants come up, they must be hoed in the same manner as is practised for turnips, cutting down all the weeds, and thinning the plants to about eight inches distant; and as they advance, and the weeds begin to grow again, they must be hoed a second time, cutting out the plants to a wider distance, so that they may finally stand a foot distant from each other. The second year they will shoot up heads which may be cut about the beginning of August. They are then to be tied up in bunches, and set in the sun

if the weather is fair: or, if not, in rooms to dry them. The common produce is about 160 bundles or staves upon an acre, which are sold for one shilling each. The leaves of the common wild teazel, dried, and given in powder or infusion, are a very powerful remedy against flatuses and crudities in the stomach. There is also another, though somewhat whimsical, use for which this plant is famous among the country people in England. If the heads are opened longitudinally, about September or October, there is generally found a small worm in them: one of these only is found in each head, whence naturalists have named it the vermis solitarius dipsaci. They collect three, five, or seven of these, always observing to make an odd number; and sealing them up in a quill, give them to be worn as an amulet against the ague. This superstitious remedy is in much higher repute than the bark, in many parts of England.

DIP'SAS. n. s. Lat. from daw, to thirst. A serpent whose bite produces the sensation of unquenchable thirst.

Scorpion, and asp, and amphisbæna dire, Cerastes horned, hydrus, and ellops drear, And dipsas.

Milton.

DIPTERA, from des and Trepov, wing, in entomology, an order of insects, which have only two wings, and under each wing a style or oblong body, terminated by a protuberance, and

called a balancer. DIPTOTE, n. s. ing of two cases only. DIPTYCH, n. s. Lat. diptycha (two leaves folded together). A register of bishops and

AITTWTα. A noun consist

martyrs.

The commemoration of saints was made out of the diptychs of the church, as appears by multitudes of places in St. Austin.

Stillingfleet. DIPTYCH, OF DIPTYCHA, in antiquity, was a public register, wherein were written the names of the consuls, and other magistrates, among the heathens; and of bishops, and living as well as dead brethren, among the Christians. The word is Greek, διπτυχα, the plural of διπτυχον, q. d. a book folded in two leaves; though there were some in three, and others in four or five leaves. This name is supposed to have been first given them to distinguish them from the books that were rolled, called volumina. There were profane diptycha in the Greek empire, as well as sacred

ones in the Greek church.

DIPUS, Gr. dinaç, i. e. two-footed, in zoology, the jerboa, a genus of quadrupeds, belonging to the order of glires, in the class mammalia. These animals were ranked by Linnæus under the genus mus; but Gmelin has, with great propriety, distributed the numerous and very different species of that genus, into nine new divisions, forming so many distinct genera, of which the dipus is one. The characters are these: there are two fore-teeth in each jaw; the tail is long, and tufted at the end; but the most striking characteristic of this genus is the enormous length of the hind feet, and extreme shortness of the fore paws. From this conformation, instead of walking or running on all fours, they leap or hop on the hind feet like birds, making prodigious bounds, and only use the fore paws for burrowing, or for

carrying their food to the mouth like squirrels. 1. D. cafer, or the Cape jerboa, has four toes on the hind feet and five on the paws; the tail is very hairy, and tipt with black. This species inhabits the Cape of Good Hope, and is fourteen inches long; the tail fifteen, the ears three. It is called aerdmannetje, or little earth man, and springen haas, or leaping hare, by the Dutch at the Cape. It has a grunting voice; is very strong, and leaps twenty or thirty feet at one bound. It burrows with its fore feet; and sleeps sitting on its hind legs, with the knees separated, the head between, and holding its ears with the fore paws over its eyes. It is eaten by the natives; and is caught by pouring water into its hole, which compels it to come out. 2. D. jaculus, the common jerboa, or leaping mouse of Linnæus, has four toes on all the feet, and a claw in place of a thumb or fifth toe on each fore foot. The body is somewhat more than seven inches long, and the hind legs and thighs are longer than the body. The upper parts are of a pale tawny color, and the under parts white: the ears and feet are flesh-colored. The female has eight teats distantly placed. These animals inhabit Egypt, Arabia, Calmuck Tartary, and southern Siberia. They frequent firm hard ground, and fields covered with grass and herbs, where they form burrows of several yards long in a winding direction, leading to a large chamber about half a yard below the surface; and from this a second passage is dug to within a very little of the surface; by which they can escape when threatened with danger. When at rest, they sit with their hind legs bent under their belly, and keep the fore legs so near the throat as hardly to be perceptible. They eat grain and herbage like the hare. Their dispositions are mild, and yet they can never be perfectly tamed. This animal is roasted and eaten by the Arabs, who call it the lamb of the children of Israel. It has been particularly described by Mr. Bruce in his Abyssinian Travels. 3. D. sagitta, the Arabian jerboa, the mus disc of the Greeks, and mus bipes of the Romans, has three toes on the hind feet, and no thumb or fifth toe on the fore paws. It is only about six inches long, and the tail rather shorter than the body; the soles of the hind feet and bottom of the toes are covered with a very thick coat of hair; the head is more rounded than that of the jaculus, and the ears are much longer than the head. It inhabits Arabia, and near the Irtish in Siberia, where it frequents the sandy plains. 4. D. Canadensis, or Canadian jerboa, is thus described by general Davies: As I conceive there are very few persons, however conversant in natural history, who may have seen or known that there was an animal existing in the coldest parts of Canada of the same genus with the jerboa, hitherto confined to the warmest climates of Africa, I take the liberty of stating the following particulars. With respect to the food, or the mode of feeding, of this animal, I have it not in my power to speak with any degree of certainty, as I could by no means procure any kind of sustenance that could induce it to eat; therefore, when caught, it lived only a day and a half. The first I was so fortunate as to catch, was taken in a large field near the Falls of Montmorenci, and, by its having

No service is appointed for the burial of the dead. All particular vestments for priests or ministers, and all saints'-days, were discarded. It has been remarked, as a considerable omission, that the Directory does not enjoin the reading of the apostles' creed, and the ten commandments. However, these were added to the assembly's confession of faith, which was published a year or two afterwards. This Directory continued in use till the restoration of king Charles II., when, the constitution being restored, the old liturgy took place again; the ordinance for its repeal having never obtained the royal assent. The revolution, thus occasioned in the form of public worship, did not take place for a considerable time over the whole kingdom. In some parts of the country the churchwardens could not procure a Directory; and in others they despised it, and continued the old common prayer book; some would read no form, and others used one of their own. In order to enforce the use of the Directory, the parliament, by an ordinance, dated August 23rd, 1645, called in all common prayer books, and imposed a fine upon those ministers who should read any other form than that contained in the Directory. By the same ordinance, which continued till the Restoration, to preach, write, or print any thing in derogation or depraving of the Directory, subjected the offender, upon indictment, to a discretionary fine, not exceeding £50.

DIRECTORY, in a more modern sense, was used as the title of the supreme executive power, according to the new constitution, formed by the French convention after the fall of Robespierre, and presented to the primary assemblies for acceptance in August, 1795. By this constitution the legislative body was composed of what they called a Council of Ancients and a Council of Five Hundred. The whole of this fabric, it is well known, was overturned by the successful ambition of Napoleon: but as it directed the energies of a numerous, if not a great, people for a considerable period, we may here perpetuate its forms. The executive power was entrusted to a Directory of five members, nominated by the legislative body as follows:-1. The Council of Five Hundred formed a list by ballot of three times the number to be nominated, and presented it to the Council of Ancients, which chose out of this list by ballot. 2. The members of the Directory were to be forty years of age at least. 3. After the ninth year of the republic, they were to be chosen only from among those citizens who had been members of the Legislative Body, or the Administration, or General Agents of Execution. 4. Members of the legislative body could not be elected members of the Directory, either during the continuance of their legislative functions, or during the first year after their expiration. 5. The Directory was partially renewed by the annual election of a new member. 6. No cidevant director could be re-elected till after an interval of five years. 7. The ascendant and descendant in the direct line; the brother, uncle, and nephew; connexions by marriage in the same degrees, and cousins in the first degree, could not be members of the Directory at the

same time, nor succeed one another in it, till after an interval of five years. 8. In case of death, removal, or resignation of a member of the Directory, his successor was elected within ten days. The Council of Five Hundred were obliged to propose the candidates within the first five days, and the Council of Ancients to complete the election within the last five. The new member could only continue in office for the remaining period of the person he succeeded, unless it did not exceed six months, in which case, he continued five years and a half in office. 9. Each director was to preside in rotation for three months only. 10. The president was to sign and keep the seal. 11. The laws and acts of the legislative body were addressed to the Directory, in the person of its president. 12. The Directory could not deliberate unless three members were present. 18. A secretary was chosen (not one of its members), who countersigned despatches, and drew up deliberations, in a register, wherein each member might also enter his opinion, with his reasons. 14. The Directory could deliberate without the aid of the secretary, and one of the directors might record its resolutions in a particular register. 15. The Directory provided for the security of the public according to the laws, issued proclamations; &c. It disposed of the armed force; but none of its members could command it, either while they continued in office, or for two years after. 16. The Directory, upon hearing of any conspiracy against the republic, might order the supposed authors or accomplices to be apprehended, and interrogate them; but were bound, under the penalty of arbitrary imprisonment to remit them to an officer of police, within two days, to proceed with them according to law. 17. The Directory nominated the generals, but could not choose them among the relations of its members, within the degrees above-mentioned. 18. It superintended the execution of the laws by commissaries of its nomination. 19. It nominated the general agents of execution, but not of its own members, and recalled them at pleasure. 20. It determined their number and functions. 21. It nominated all receivers of direct taxes. 22. As well as the superintendants of indirect contributions, and the administration of national domains. 23. It superintended the coinage of money, and nominated the officers charged with it. 24. No Director could go out of the territory of the republic, till two years after he was out of office; but was obliged to certify his place of residence during that interval to the legislative body. 25. The Directory was responsible for the non-execution of laws, and for the abuses which it did not denounce. 26. Its agents were respectively responsible for the non-execution of the laws, and orders of the directory. 27. Its members might be tried by the legislative body for acts of treason, corruption, embezzlement of public money, and all capital crimes as to their official conduct. 28. They were subject to the jurisdiction of the tribunals for ordinary and private offences; but they could not be arrested except in the case of flagrans delictum, or brought to trial without the authority of the legislative body.

Every denunciation against the Directory, or