sequence. The principle of this method of reasoning is commonly described as subsumption: the conclusion is shown to fall under or be included in the more fundamental propositions which are assumed as the starting point. These latter propositions can similarly be derived from others of still greater generality, until at last we reach the ultimate principles which form the foundation of all science. As to the foundation on which the ultimate principles themselves rest, various theories have been held. Until comparatively recent times the prevailing view (though by no means universally adopted) has maintained that these propositions neither require nor admit of any demonstration. They are necessary intuitions of the mind whose certainty is direct and immediate, and of a higher type than demonstrations can yield. They thus constitute the basis of all science, since they are the fundamental first truths to which all science appeals as to an unquestioned authority. In the 17th and 18th centuries particularly, mathematics was regarded as the ideal science, and the position of the indemonstrable first principles of all science was often paralleled with that of the axioms of mathematics. It was assumed before the time of Kant that mathematics was wholly a deductive science which derived its results through an analysis of its initial concepts. In like manner it was hoped to put all knowledge on a demonstrative basis by discovering the whole system of necessary truths, and by showing how all particular facts in the various fields could be derived from them; for this would afford the absolute certainty which science was supposed to demand, i.e., every fact would be deduced as a necessary consequence from some general principle. At this time the empirical conclusions reached by inductive reasoning were not regarded as worthy of the name of science, for they are not universal and necessary truths, but only particular and more or less probable.

The development of thought in recent times has, however, entirely revolutionized our ideal of knowledge, and at the same time broken down the sharp distinctions between necessary, or a priori principles, and empirical truth, as well as between induction and deduction as contrasted methods of reasoning. It is now generally recognized that there are no a priori truths in the old sense; no propositions that are certain in themselves apart from their connection with the rest of experience. No matter how ultimate any truth may appear, or how necessary in itself, its certainty and necessity are mediated in and through its relation to other experienced facts with which it is connected in the organic unity of a system. It is only through this systematic connection of the parts of knowledge that any inference is possible. For it is only in a whole, where the parts are systematically connected, that the nature of one part enables us to say what the other parts must be. And when it is seen that reasoning consists in making explicit the systematic connections of facts, the contrast between induction and deduction falls away. The structure of every inference is essentially the same; every inference is constituted by the relating of facts through a general principle. In deduction, as we have seen, the general truth is the starting

point and we go on to explicate it in its application to some particular group of facts. On the other hand, the problem may be to find some relating principle for a given group of facts; and here we have to work in the reverse direction, beginning with the particulars and by the use of inductive methods seeking to bring to light some universal principles of connection. There are no sciences which use exclusively either one of these methods. Even mathematics, which popularly is supposed to employ only deductive reasoning, has constantly to appeal to induction of particular observations; and, on the other hand, the so-called observational sciences reason deductively in tracing out the application of the laws which have already been discovered and the consequences of the hypotheses which are employed. In every field thought uses all the means and methods which it can command to aid in solving its pro.lems. Induction and deduction, observation and reasoning, are not separate and isolated processes, but functions of the knowledge-process which are supplementary and go hand in hand.

JAMES E. CREIGHTON, Professor of Philosophy, Cornell University.

Dee, John, English astrologer: b. London 13 July 1527; d. Mortlake, England, 1608. In early life he had devoted much of his time to mathematical, astronomical, and chemical studies; and in 1548 rumors began to prevail that he was addicted to the black art. They were probably well founded; and to avoid the consequences he went abroad. In 1551 he returned to England, and through the instrumentality of Cecil, who presented him to Edward VI., obtained a pension of 100 crowns. The suspicion of the black art appears still to have clung to him, and shortly after Queen Mary's accession he was charged with practising against the queen's life by enchantment, and imprisoned. He obtained his liberty in 1555, and after Queen Elizabeth's accession was consulted by Lord Dudley as to "a propitious day" for the coronation. Lilly's account of him is that he was the queen's intelligencer, with a fixed salary; a great investigator of the more secret hermetical learning, a perfect astronomer, a curious astrologer, a serious geometrician, and excellent in all kinds of learning. The nature of his employments excited strong suspicion, and in 1576 he was furiously attacked by a mob, from which he had difficulty in escaping with his life. In 1578, during an illness of the queen, he was sent to consult with the German physicians and philosophers as to her recovery, and after his return was employed to draw up a sketch of the countries which, from having been discovered by English subjects, belonged to the crown. He accordingly prepared two rolls, giving both a geographical description and a historical account of the countries. These curious documents are still extant in the British Museum. After many wanderings, Dee, returning home, obtained from the queen in 1595, the wardenship of Manchester College, which he held nine years. It has been supposed, with some plausibility, that Dee's character as an alchemist was merely assumed to enable him to act more securely and effectually as a spy in the employment of the English government.

Dee, the name of several British rivers. 1. A river in Scotland, partly in Kincardineshire, but chiefly in Aberdeenshire, one of the best salmon rivers in Great Britain. It rises on the southwest border of Aberdeenshire, and flows generally east, 87 miles to the German Ocean. The city of Aberdeen is at its mouth. 2. A river of North Wales and Cheshire; rises in Lake Bala, Merionethshire; flows north-northeast and northwest to the Irish Sea, 20 miles below Chester; length, about 80 miles. 3. A river of Scotland, county of Kirkcudbright, rises in Loch Dee. It flows southeast and south into Kirkcudbright Bay; length, 38 miles.

Deed, a written instrument under seal, containing a contract or agreement which has been delivered by the party to be bound and accepted by the obligee or covenantee. It has also been defined as follows: "A writing containing a contract sealed and delivered by the party thereto." (2 Wash. Real Prop. 553.) The law requires greater form and solemnity in the conveyance of land, than in that of chattels. This arises from the greater dignity of the freehold in the eye of the ancient law, and from the light and transitory nature of personal property, which enters much more deeply into commerce, and requires the utmost facility in its incessant

circulation.

In the early period of English history the conveyance of land was ordinarily without writing, but it was accompanied with overt acts, equivalent, in point of formality and certainty, to deeds. As knowledge increased, conveyance by writing became more prevalent and ultimately by the statute of frauds and perjuries, of 29 Charles II., Ch. 3, secs. I, 2, all estates and interests in lands (except leases not exceeding three years) created, granted, or assigned, by livery of seisin only, or by parol, and not in writing, and signed by the party, were declared to have no greater force or effect than estates at will only. And by the fourth section no person could be charged upon any "contract or sale of lands, or any interest in or concerning the same, unless the agreement or some memoran dum or note thereof, was in writing, and signed by the party to be charged therewith, or some other person by him lawfully authorized.

With some trivial changes this statute provision has been adopted or assumed as law throughout the United States. Deeds must be upon paper or parchment, must be completely written before delivery, must be between competent parties, and certain classes are excluded from holding lands, and, consequently from being grantees in a deed; must be made without restraint; must relate to suitable property, and should be signed, sealed, and delivered. The consideration of a deed must be good or valuable and not partaking of anything immoral, illegal, or fraudulent.

A deed should be delivered and accepted. A delivery is the transfer of a deed from the grantor to the grantee, or some other person acting in his behalf, in such a manner as to deprive the grantor of the right to recall it at his option. An absolute delivery is one which is complete upon the actual transfer of the instrument from the possession of the grantor. A conditional delivery is one which passes the deed from the possession of the grantor, but is not to be completed by possession in the grantee,

or a third person as his agent, until the happening of a specified event. A deed delivered in this manner is an escrow, and such delivery should be always made to a third person. No particular form of procedure is required to effect a delivery. It may be by acts merely, by words merely, or by both combined, but in all cases an intention that it shall be a delivery must exist. It may be made by an agent as well as by the grantee himself. To complete a delivery, an acceptance must take place, which may be presumed from the grantee's possession. In a deed the premises embrace the statement of the parties, the consideration, recitals inserted granted, with the intended exceptions. The for explanation, description of the property habendum begins at the words "to have and to hold," and limits and defines the estate which the grantee is to have. The reddendum, which is used to reserve something to the grantor; the conditions; the covenants; and the conclusion which mentions the execution date, etc., constitute the formal parts of a deed and properly follow in the order observed here. The construction of deeds is favorable to their validity; the principal includes the incident; punctuation is not regarded; a false description does not harm; the construction is least favorable to the party making the conveyance or reservation; the habendum is rejected if repugnant to the rest of the deed. The lex rei site governs in the conveyance of lands, both as to the requisites and the forms of conveyances.

Chancellor Kent, after observing that in the United States generally the form of conveyance is very simple, says: "I apprehend that a deed would be perfectly competent, in any part of the United States, to convey the fee if it was to the following effect: I, A. B., in consideration of one dollar to me paid by C. D. do grant, bargain and sell to C. D. and his heirs, the lot of land (describe it), witness my hand and seal, etc.>>>

Deeg, deg, India, town and dismantled fortress in Rajputana, state of Bhurtpore, 24 miles west of Muttra. It is situated in the midst of marshes, and almost surrounded by water during a great part of the year. At the southwest corner is the lofty rock of the Shah Boorj, on which the citadel stands. Deeg is a place of great antiquity, and contains a remarkably fine palace, only surpassed in beauty by the Taj Mahal of Agra. Holkar was defeated here by the British under Gen. Fraser in November 1804, and the following month the town and fortress were taken. Pop. 16,000.

Deems, Charles Force, American clergyman and writer: b. Baltimore, Md., 4 Dec. 1820; d. New York 18 Nov. 1893. From 1866 to his death he was pastor of the Church of the Strangers of New York, and was widely known as editor and author. Included in his publications are: 'Triumph of Peace and Other Poems' (1840); The Light of the Nations' (1870); Weights and Wings' (1872); Chips and Chunks for Every Fireside'; and 'My Septuagint) (1892).

Deemster, an officer once attached to the high court of justiciary in Scotland, who formally pronounced the doom or sentence of death on condemned criminals. The office was conjoined with that of executioner. The name is now given in the Isle of Man to two judges who

length is about 125 miles; it has good water power, some of which is utilized at Lockville.

Deep-sea Exploration. The exploration of ocean depths dates from 1867, when Pourtales and Mitchell, officers of the United States Coast Survey, engaged in systematic sounding and dredging in the Straits of Florida. From 1868 to 1872 a similar work was undertaken by Wyville Thomson, carpenter, and George Jeffries, in British vessels, sounding the Mediterranean and North Atlantic. Beginning in December 1872, and continuing until the spring of 1876, the Challenger, a British ship, under Nares and Thomson, made a tour of the world, taking soundings and dredging from 362 stations. France and Norway sent out expeditions for a like purpose at a later date. The Prince of Monaco also took great interest and did much sounding from his yacht, bringing up fish from a depth of two miles. Excepting the successful and complete work of the Challenger, most of the exploration valuable to science has been done by the United States, the Bibb making a tour in 1868-9, and the Blake doing continuous duty in this field from 1877 to 1880, under the co-operation of Agassiz, Sigsbee, and Bartlett, while the United States fish commission vessels, Albatross and Fishhawk, engaged in lengthy exploration under Baird, Belknap, Tanner, etc.

The average depth of the ocean is now known to be about 21⁄2 statute miles. Its floor has a contour very similar to that of the land, there being vast levels or plains, ravines, gorges, ridges and mountains that rise into islands, and deeps that fall farther below the sea-level than the topmost peaks of the Himalayas rise above that level. Light penetrates about 100 fathoms, or in specially clear water, under the direct rays of a tropical sun, to perhaps nearly 200 fathoms, and below it is all dark, except for the phosphorescence of some of the deep-sea inhabitants. The depths are also cold, approaching the freezing point in all latitudes. The cold waters from the frozen poles flow in slow currents along the bottom, over the dead marine organisms that strew the greater portion of the ocean floors, down to the deepest regions, where the bottom is of red clay of Tertiary formation.

The 100-fathom depth to which light penetrates has been termed the littoral region, and within this grow marine algæ, and the animals that feed upon them. The depths below 1,000 fathoms have been termed the benthal area, while the area between 100 and 1,000 fathoms has been termed the abyssal area. The slopes along the edges of the continents, extending roughly 200 miles from land, constitute the region of terrigenous deposits, the sea bottom being composed more or less of the washings carried down by the great rivers that drain the continents. Besides the washings, which partake of the nature of the adjoining land, this region contains green coral, and volcanic mud. Beyond the influence of the shore washings comes the region of pelagic deposits, the ocean floor being strewn with dead marine organisms that have sunk from the littoral region.

The immense pressures of the great deeps below 3,000 or 4,000 fathoms are probably accountable for the fact that the dead organisms (so common to higher regions) are not found, but apparently dissolve and float away in the currents. The deepest holes have a bottom of

red clay that appears to have undergone no material change since the Tertiary Period.

Since there are no algæ below the littoral region, it follows that all the marine animals below are carnivorous. None of these are ever brought up alive, since, if alive when netted, they succumb to the expansion that results from their being brought up to the surface where the pressure is so much below what they are constructed to reside in. The sea pressures are enormous, increasing from 15 pounds per square inch at the surface to a ton per square inch at a depth of 1,000 fathoms. The fish brought up from a depth of 3,000 fathoms are therefore subject to a surrounding pressure of three tons per inch of surface, a pressure that would be dangerous to a high-grade steel boiler. The deepsea fishes do not succumb to it, because their tissues are porous, and the fluids of their bodies are of a like pressure with their surroundings. This maintains a balance that subjects them to no more strain than would a solid shot receive by being immersed at the same pressure. The bones of these fishes, instead of being built heavy to withstand a crushing pressure, are made fibrous and full of porosities, and include scarcely any calcareous matter. When these fish are brought to the surface their joints and muscles are found to be very loosely connected, and they have to be handled very carefully. Some of them are sure to break up with the least handling, as the Plagiodus of the Madeiran Sea. The deep-sea fishes universally are provided with airbladders, and these of course tend to expand as the fish are brought up. Probably they could be brought up alive, if the speed of raising them were very slow. There are many deep-sea fishes that live at or near the surface when quite young, and go deeper as they advance in age. Nearly all the deep-sea fishes are classified among the same families as the fishes familiar on the surface, but the Alepocephalide and Halosaurida are found only in the depths.

At a depth of 400 fathoms the Gobiida, Blenniidæ, Percidæ, Scorpænidæ, Trichiuride, Coltoida, Cataphracti, Bathythrisside, and most of the Trachinida cease to exist. At a depth of 500 fathoms the sharks, rays, and flatfish are no longer found. At a depth of 700 fathoms the Cottoida, Discoboli, Zoarcide, etc., disappear. The limit of the Holocephali is about 1,200 fathoms. The families commonly found at the greatest depths, 2,500 fathoms and under, are the Berycidæ, Ophidiida, Pediculati, Macrurida, Sternoptychida, Scopelida, Stomiatida, and Muranidæ.

Both the number and variety of fish decrease as depths increase, as the vast body of marine animals prefer to live near the surface.

The phosphorescent fishes are mostly characterized by luminous organs, which present all sorts of modifications as to location, appearance, and structure. Some of them are luminous all over when in motion and non-luminous when at rest, the brightness being occasioned by a luminous secretion emitted when the creature is active. Some of the deep-sea creatures are blind, others see by phosphorescent light, which they or other organisms emit. The fishes in the very great depths have small eyes, while those of moderate depths have large optical organs. Many deep-sea animals have highly developed feelers; the coloration of others is extremely

brilliant, yellows, reds, greens, and purples being dominant colors, while there is a strange absence of blue. The fishes are mostly darkcolored, while the crustaceans, holothurians and starfish are the most brilliant, the colors being often in large patches of striking contrast. No deep-sea fishes above about five feet in length have been taken. This is not regarded as evidence that they do not grow longer, the fact that the mouths of the largest beam-trawls in use are only about II by 2 or 3 feet probably having something to do with the matter.

The dredge or beam-trawl commonly used is a form of big bag-net, of 20 to 25 feet in length, that is weighted and dragged along the bottom. As many as 800 fishes have been brought up in a single haul with such a dredge, from a depth of 1,770 fathoms, in Bering Sea. Four or five hours are required to dredge at such a depth. The deepest haul on record at which animal life was obtained was made by the Albatross of the United States Fish Commission, near the Tonga Islands, the depth being 4,173 fathoms. Ten hours elapsed from the time the dredge went overboard till it was brought again to the deck.

The tangle is a device used for bringing up specimens of fauna or anything it can catch. This consists of an iron bent in the form of an inverted V and having frayed rope attached to it. During recent years gill-nets have been used at a depth of a mile, and traps and trawl-lines have also been sunk to considerable depths.

The first reliable sounding at a great depth is credited to Capt. Sir James Clark Ross, who in 1840 sounded 2,677 fathoms on the west coast of Africa. Subsequent soundings were reported as deep as 7,000 fathoms, but as these were made with the old-fashioned clumsy apparatus that tended to drift tremendously, and as they do not agree with modern soundings, they are not credited. In 1854 J. M. Brooke of the United States navy, suggested the employment of a dropped weight in deep-sea sounding, and this was found to assist matters so much that it has remained in use ever since. The first attempts to substitute wire for rope were not very satisfactory, owing to the too great thickness and weight of the wire used. When steel piano-wire of great tensile strength was brought into use and weighted with a 60-pound shot, arranged to be dropped, it was found that the soundings were made with a close approach to accuracy, and at much greater speed in much less time than before.

In 1872 there was invented the cylinder sounding machine in which a cannon-ball was used for the sinker, the ball having a hole bored through it, in which was placed a metal tube or small cylinder. When the weight descended into the muddy bottom, the tube was filled with mud, and a device closed it, at the same time releasing the ball. Another device originated later consists of two hemispherical cups, normally hinged so as to be apart. When the weight strikes the bottom it brings the cups together, so that they grasp whatever is in the way. The wire used in soundings weighs about 14 pounds to the mile, and very ingenious reeling-machines have been devised for handling it. The first difficulty to be overcome was the roll of the ship, which tended to jerk the line. This is compensated for, and a friction device is adjustable so as to balance the weight of wire, etc.,

that is out. Elastic appliances, called accumulators, were devised by C. D. Sigsbee of the United States navy, and these have made it possible to employ steam power in paying out and reeling in the line.

The testing of deep-sea currents is done with the current-meter, the accepted form of which is hung on a wheeled traveler from the line sent down. A screw-propeller-like device rotates with the current, and there is a contrivance for registering the number of revolutions, from which registration the speed can be computed. The older devices, which were less satisfactory, depended upon the differential motion of surface floats to note the difference between upper and lower currents.

When it was first endeavored to take temperatures by thermometers at considerable depths it was found that the results were erroneous, apparently because of the increased pressure. Miller and Cassella invented a double thermometer that partially overcame the difficulty, but it served to register only the maximum and minimum temperatures. Negretti and Zambra improved on this, arranging the thermometer in reversed position while descending, and bringing it back to proper position at the depth of the test. The turn resulted in separating the column of mercury above the bulb, and the correct temperature could be indicated.

A most ingenious apparatus for reading the temperature of a descending sounding apparatus from the deck of a vessel has been designed by Sir William Siemens. He secures the temperature on the Wheatstone bridge principle, by the electric resistance of a conductor. A copper vessel of water is heated or cooled until the bridge balances, and the temperature of the water in the vessel is then the same as that below. The apparatus is unfortunately too delicate for ordinary use. All instruments sent down into the depths have to be protected against the pressure, their strength being proportioned to the depths to which they are to be used.

The deepest sounding made up to 1876 was that of the Tuscarora, of the United States Fish Commission, which reached 4,655 fathoms off the coast of Japan, in 1874. The Challenger's deepest sounding was also in Japanese waters, near the Admiralty Islands, the depth being 4,575 fathoms. In 1896 the British ship Penguin got 5,155 fathoms north of New Zealand, breaking the record. This was the deepest found until 1900, when the United States cable survey ship Nero found a depth of 5,269 fathoms near Guam. Other deep soundings are those of the Albatross of the United States Fish Commission, which located a depth of 4.813 in the western Pacific, and of the Blake of the United States Coast Survey, which sounded 4,561 fathoms off Porto Rico, this being the deepest yet recorded in the Atlantic Ocean. No deep places have been found north of the 55th degree of latitude, which tends to confirm the theory of some that the Arctic Ocean is shallow. Consult: Agassiz, Three Cruises of the Blake'; Sigsbee, DeepSea Sounding and Dredging); Tanner, 'DeepSea Exploration.

CHARLES H. COCHRANE.

Deep-sea Life. It is difficult to draw the line between deep-sea life and that of shallow water, owing to the various depths in which certain species live. Thus the common shore-crab