the U. States, and the circuit courts, are invested with general equity powers, and act either as courts of law or equity, according to the form of the process and the subject of adjudication. In some of the states, as New York, Virginia and South Carolina, the equity court is a distinct tribunal, having its appropriate judge, or chancellor, and officers. In most of the states, the two jurisdictions centre in the same judicial officers, as in the courts of the U. States; and the extent of equity jurisdiction and proceedings is very various in the different states, being very ample in Connecticut, New York, New Jersey, Maryland, Virginia and South Carolina, and more restricted in Maine, Massachusetts, Rhode Island and Pennsylvania. But the salutary influence of these powers on the judicial administration generally, by the adaptation of chancery forms and modes of proceeding to many cases in which a court of law affords but an imperfect remedy, or no remedy at all, is producing a gradual extension of them in those states where they have been heretofore very limited. (See Chancellor, Common Law, and Courts.) in many cases, an exclusive jurisdiction. This it does in all cases of merely equitable rights, that is, such rights as are not recognised in courts of law. Most cases of trust and confidence fall under this head. Its exclusive jurisdiction is also extensively exercised in granting special relief beyond the reach of the common law. It will grant injunctions to prevent waste, or irreparable injury, or to secure a settled right, or to prevent vexatious litigations, or to compel the restitution of title deeds; it will appoint receivers of property, where it is in danger of misapplication; it will compel the surrender of securities improperly obtained; it will prohibit a party from leaving the country in order to avoid a suit; it will restrain any undue exercise of a legal right, against conscience and equity; it will decree a specific performance of contracts respecting real estates; it will, in many cases, supply the imperfect execution of instruments, and reform and alter them according to the real intention of the parties; it will grant relief in cases of lost deeds or securities; and, in all cases in which its interference is asked, its general rule is, that he who EQUITY OF REDEMPTION. Upon a mortasks equity must do equity. If a party, gage, although the estate, upon nonpaytherefore, should ask to have a bond for ment of the money, becomes vested in the a usurious debt given up, equity could mortgagee, yet equity considers it only a not decree it unless he could bring into pledge for the money, and gives the party court the money honestly due without a usury. This is a very general and imperfect outline of the jurisdiction of a court of equity; in respect to which it has been justly remarked, that, in matters within its exclusive jurisdiction, where substantial justice entitles the party to relief, but the positive law is silent, it is impossible to define the boundaries of that jurisdiction, or to enumerate, with precision, its various principles. (Those who wish for more information on the subject may consult the elementary treatises of Fonblanque on Equity, lord Redesdale's Treatise on Equity Pleadings, and Cooper's Equity Pleadings; and the Practical Treatises of Equity by Maddock and Jeremy.) Equity, Courts of. The equity jurisdiction, in England, is vested, principally, in the high court of chancery. (See Chancellor.) The court is distinct from the courts of law. American courts of equity are, in some instances, distinct from those of law; in others, the same tribunals exercise the jurisdiction both of courts of law and equity, though their forms of proceeding are different in their two capacities. The supreme court of right to redeem, which is called his equity of redemption. If the mortgagee is desirous to bar the equity of redemption, he may oblige the mortgager either to pay the money or be foreclosed of his equity, which is done by proceedings in chancery by bill of foreclosure. (See Mortgage.) EQUIVALENTS, CHEMICAL; a term employed in chemical philosophy, to express the system of definite ratios, in which the corpuscular subjects of this science reciprocally combine, referred to a common standard, reckoned unity. The principal facts relating to chemical combinations require to be stated, in order to render the present subject intelligible. And in the first place, leaving out of view the combinations of liquids with each other, and the common cases of solution in water and alcohol, the first law relating to the combination of substances is, that the composition of bodies is fixed and invariable; or, in other words, a compound substance, so long as it retains its characteristic properties, always consists of the same elements, united together in the same proportion. Sulphuric acid, for example, is always composed of sulphur and oxygen, in the ratio of 16 parts, by weight, of the former, to 24 of the latter; no other elements can form it, nor can its own elements form it in any other proportion. Sulphate of barytes, in like manner, is always composed of 40 parts of sulphuric acid and 78 of barytes. If sulphuric acid and barytes should enter into combination in any other proportion, some new compound, different from sulphate of barytes, would be formed. The second law relating to this subject is, that, when one body combines with another in different proportions, the larger proportion of one of the ingredients has a simple arithmetical ratio to the smaller proportion;-the second quantity being a simple multiple of the first; and if there is a third or fourth proportion, the same ratio continues between them. The combinations of the two substances, which, in their gaseous state, form, by their mixture, the atmosphere,oxygen and nitrogen,-unite in five different proportions, and form a good illustration of this law, these proportions having to each other the simple ratio of 1, 2, 3, 4, 5. Nitrogen. Oxygen. Nitrous oxide consists of 14 Nitric oxide, Hypo-nitrous acid, Nitrous acid, Nitric acid, 14 16 14 24 14 32 14 40 To give an example from the salts, the bicarbonate of potash contains twice as much carbonic acid as the carbonate; and the oxalic acid of the three oxalates of potash is in the ratio of 1, 2, and 4. This law is often called the law of multiples, or of combination in multiple proportion. It has been established only by comparatively recent investigations, but the most rigid researches have abundantly evinced that it is a well-founded law. The third law of combination is no less remarkable than the preceding, and is intimately connected with it. Water and hypo-sulphurous acid may be adduced for its illustration. The former is composed of 8 oxygen to 1 hydrogen; the latter of 8 oxygen to 16 sulphur. Now, the well-known substance sulphureted hydrogen is constituted of 1 hydrogen to 16 sulphur; that is, the quantities of hydrogen and of sulphur, which combine with the same quantity of oxygen, combine with one another. Again, 40 parts of selenium, with 8 of oxygen, form the oxide of selenium, and, with 1 of hydrogen, seleniureted hydrogen; 36 parts of chlorine, with 8 of oxygen, constitute the oxide of chlorine, and, with 1 of hydrogen, form muriatic acid When one body combines with another in more than one proportion, then the law of multiples, already explained, comes into action. Thus Hypo-sulphurous) Sulphur, acid is com-16 or 1 pr. +8 or 1 pr. posed of Sulphurous acid, Sulphuric acid, Oxygen. 16 or 1 pr. 16 or 2 pr. 16 or 1 pr. 24 or 3 pr. The most usual combination is 1 proportion of one body either with 1 or with 2 proportions of another. Combinations of 1 to 3, or 1 to 4, are very uncommon, unless the more simple compounds likewise exist. But this law does not apply to elementary substances only, since compound bodies have their combining proportions, which may likewise be expressed in numbers. Thus, since water is composed of one proportion, or 8, of oxygen, and one proportion, or 1, of hydrogen, its combining proportion is 9. The proportion of sulphuric acid is 40, because it is a compound of one proportion, or 16, of sulphur, and three proportions, or 24, of oxygen; and, in like manner, the combining proportion of muriatic acid is 37, because it is a compound of one proportion, or 36 of chlorine, and one proportion, or 1, of hydrogen. The proportional number of potassium is 40, and, as that quantity combines with 8 of oxygen to form potash, the combining proportion of potash is 48. Now, when these compounds unite, one proportion of the one combines with one, two, three or more proportions of the other, precisely as the simple substances do. The hydrate of potash, for example, is constituted of 48 potash and 9 of water, and its combining proportion is, consequently, 48+9, or 57. The sulphate of potash is composed of 40 sulphuric acid + 48 potash. The combining proportion of this salt is, therefore, 88. The muriate of the same alkali is composed of 37 muriatic acid +48 potash; its combining proportion is, therefore, 85. The composition of the salts affords an excellent illustration of this subject; and, to · exemplify it still further, a list of the proportional numbers of a few acids and alkaline bases is subjoined. Magnesia, Fluoric acid,.. 10 Lithia,. 32 48 52 78 which contain the smallest proportion of oxygen or hydrogen in combination with some other substance, the quantities of each being the smallest that can unite together. Carbonic oxide with respect to carbon, and sulphureted hydrogen with respect to sulphur, answer this description 18 perfectly. The former consists of 8 oxy20 gen and 6 carbon; the latter of 1 hydro28 gen and 16 sulphur. The proportional number of carbon is, consequently, 6, and of sulphur, 16. The proportions of all other bodies may be determined in the same manner. Since the proportional numbers merely express the relative quantities of different substances which combine together, it is, in itself, immaterial what figures are employed to express them. The only essential point is, that the relation should be strictly observed. Thus we may make the combining proportion of hydrogen 10; but then oxygen must be 80, carbon 60, and sulphur 160. Doctor Thomson makes oxygen 1, so that hydrogen is eight times less than unity, or 0.125, carbon 0.75, and sulphur 2. Doctor Wollaston fixes oxygen at 10, by which hydrogen is 1.25, carbon 7.5, and so on. According to Berzelius, oxygen is 100. The system of Wollaston becomes the same as doctor Thomson's by merely dividing by 10; that is, by placing the decimal point more to the left by one figure; and then, if we multiply by 8, it is converted into Mr. Dalton's scale, in which hydrogen is the standard.-Tables of the combining quantities of all chemical agents have been drawn up and arranged to guide the chemist in experimental researches. The utility of these tables is very extensive. Through their aid, and by remembering the proportional numbers of a few elementary substances, the composition of a great number of compound bodies may be calculated with facility. By knowing that 6 is the combining proportion of carbon and 8 of oxygen, it is easy to recollect the composition of carbonic oxide and carbonic acid,-the first being 6 carbon +8 oxygen, and the second 6 carbon +16 oxygen. 40 is the number of potassium, and potash, being its protoxide, is composed of 40 potassium +8 oxygen. From these few data, we know at once the composition of the carbonate and bicarbonate of potash. The first is 22 carbonic acid + 48 potash; the second, 44 carbonic acid +48 potash. These tables are rendered still more useful, if accompanied by a logometric sliding scale, the application of which to this purpose was a happy inven Potash, Strontia, Barytes,. Now bodies uniting according to their proportional numbers, as has been seen above, the proportion of each base expresses the precise quantity required to neutralize a proportion of each of the acids. Thus 18 of lithia, 32 of soda, and 78 of barytes combine with 10 of fluoric acid, forming the neutral fluates of lithia, soda and barytes, and are termed equivalents of each other, as well as of fluoric acid. The same fact is obvious, with respect to the acids; for 28 of phosphoric, 40 of sulphuric, and 62 of arsenic acid unite with 28 of lime, forming a neutral phosphate, sulphate and arseniate of lime, and these acids, in like manner, are equivalents of each other and of lime. These circumstances afford a ready explanation of the fact, that when two neutral salts mutually decompose one another, the resulting compounds are likewise neutral. If 88 parts of neutral sulphate of potash are mixed with 132 of the nitrate of barytes, the 78 barytes unite with the 40 sulphuric acid, and the 54 nitric acid of the nitrate combine with the 48 potash of the sulphate-not a particle of acid or alkali remaining in an uncombined condition. The method of determining the proportional numbers, as might be anticipated from what has gone before, is, to analyze a definite compound of two simple substances which possess an extensive range of affinity. No two bodies are better adapted for this purpose than oxygen and hydrogen, and that compound of these is selected which contains the smallest quantity of oxygen. Water is such a substance; and it is therefore regarded as a compound of one proportion of oxygen to one proportion of hydrogen. But analysis proves that it is composed of 8 parts of the former to 1 of the latter, by which the relative weights of their proportions are determined, that of oxygen being eight times heavier than that of hydrogen. Some compounds are next examined tion of doctor Wollaston. As it is not possible to include, on a single scale, the names of all substances, those are selected which are the most frequent subjects of reference. These are arranged in the order of their relative weights, and at such distances from each other, according to their weights, that the series of numbers, placed on a sliding scale, can at pleasure be moved, so that any number expressing the weight of a compound may be brought to correspond with the place of that compound in the adjacent column. The arrangement is then such that the weight of any ingredient in its composition, of any reagent to be employed, or precipitate that might be obtained in its analysis, will be found opposite the point at which its respective name is placed. Let us illustrate its use by a few examples. 1. The quantity of any substance, which is equivalent to a given quantity of any other inscribed on the scale, may be learned by inspection; the quantities taken being quite arbitrary, and such as are liable to suit the purpose at any time. Thus, by bringing 50, on the slider (in a scale where the weight of hydrogen is expressed by 1), opposite to magnesia, or to its equivalent, 20, it will be seen that 50 parts of that earth are equivalent to 70 lime, 120 potash, &c. 2. It ascertains the quantity of each base that is equivalent to a given quantity of any acid. Thus 50 on the slider being brought opposite to sulphuric acid, or to its equivalent, 40, it appears that 50 parts of this acid saturate 25 of magnesia, 35 lime, 60 potash, &c. In a similar manner, it is capable of indicating the quantities of different acids required to saturate each base; thus 50 parts of magnesia saturate 100 of sulphuric acid, 135 nitric acid, &c. 3. It enables us to determine, by inspection, the proportions of the components in a given quantity of any substance of known composition. Thus, by bringing 100, on the slider, opposite to 72, the equivalent of dry sulphate of soda, we find 55.5 on the slider, opposite to the equivalent of sulphuric acid, and 44.5 opposite to the equivalent of soda; numbers which, together, make up 100 of the salt. It expresses not only the proximate, but the ultimate elements of compounds. Thus, keeping the slider in the same situation as above, we find 22.4 on the slider, opposite to 16, the equivalent of sulphur, and 33.1 opposite to 24, the equivalent of three proportions of oxygen; and 22.4+33.1 make up, together, 55.5 of sulphuric acid. By reference to the equivalents of sodium and VOL. IV. 48 oxygen, we find, also, that 44 parts of soda are made up of 33 sodium and 11 oxygen. 4. The quantity of any substance required to decompose a given quantity of another, by simple elective attraction, is at once taught by the scale. Thus, if we wish to know the smallest quantity of sulphuric acid adequate to decompose 100 parts of chloride of sodium, by bringing 100, on the slider, opposite to chloride of sodium, or its equivalent, 60, we find 661, on the slider, opposite to 40, the equivalent of dry sulphuric acid, and opposite to 49, the equivalent of sulphuric acid of commerce, we find 81 of the latter. We must, therefore, employ 663 of the former, or 81 of the latter. Again, to know the quantity of dry sulphate of soda which would result if all the common salt were decomposed, we shall find 120, on the slider, opposite to the dry sulphate, or to its equivalent, 72, and 270 opposite to the crystallized sulphate, or to its representative number, 162. 5. The quantities of salts, each consisting of two ingredients, that are required for mutual decomposition, may be learned by a similar use of the sliding scale. Supposing, for instance, that we have 83 parts of sulphate of potash, and wish to know the quantity of chloride of barium required for their decomposition; bring 83, on the slider, opposite to sulphate of potash, or to 88, its representative, and opposite to 106, the equivalent of chloride of barium; we find 100 on the slider, which is the number required. The results of this decomposi tion may also be learned by examining the instrument when in the same situation of the slider; for opposite to the equivalent of sulphate of barytes, 118, we find on the slider 111, and opposite to chloride of potassium we find 71.5 on the slider, the two last numbers indicating the resulting quantities of the new compounds. Again, from the weight of a precipitate, it is easy to deduce the quantities of salts which have afforded it. Thus, if we had obtained by experiment 120 parts of dry sulphate of barytes, on bringing that number opposite to its equivalent, 118, we see at once that they may have resulted from 89 of sulphate of potash, and 108 of chloride of barium; and moreover, that 120 parts of barytic sulphate are composed of 40.6 sulphuric acid, and 79.4 barytes; the sulphuric acid consisting of 16.5 sulphur and 24.1 oxygen, and the barytes of 8.15 oxygen and 71.25 barium. Other applications still, of the scale of chemical equivalents, are pointed out by dector Wollaston in his memoir, explana tive of its principle and uses, in the Phil. Trans. for 1814; but the accurate and ready solution of so many important practical problems as have been noticed above are sufficient to show its importance to the chemist. Doctor Ure remarks of it, that it is "an instrument which has contributed more to facilitate the general study and practice of chemistry than any other invention of man." ERA. (See Epoch, and Era.) ERASMUS, Desiderius, born at Rotterdam, 1467, was the illegitimate son of a Dutchman of Gouda, by name Gerard, and the daughter of a physician. He was a singing-boy in the cathedral of Utrecht till his ninth year, then entered the school at Deventer, where he displayed such brilliant powers, that it was predicted that he would be the most learned man of his time. After the death of his parents, whom he lost in his fourteenth year, his guardians compelled him to enter a monastery; and, at the age of seventeen, he assumed the monastic habit. The bishop of Cambray delivered him from this constraint. In 1492, he travelled to Paris, to perfect himself in theology and polite literature. He there became the instructer of several rich Englishmen, from one of whom he received a pension for life. He accompanied them to England in 1497, where he was graciously received by the king. He returned soon after to Paris, and then travelled into Italy to increase his stock of knowledge. In Bologna, where he received the degree of doctor of theology, he was one day mistaken, on account of his white scapulary, for one of the physicians who attended those sick of the plague; and, not keeping out of the way of the people, as such persons were required to do, he was stoned, and narrowly escaped with his life. This accident was the occasion of his asking a dispensation from the vows of his order, which the pope granted him. He visited Venice, Padua and Rome; but, brilliant as were the offers here made him, he preferred the invitation of his friends in England, where the favor in which he stood with Henry VIII promised him still greater advantages. When he visited the lord chancellor sir Thomas More without making himself known to him, the chancellor was so delighted with his conversation, that he exclaimed "You are either Erasmus or the devil." He was offered a benefice, but was unwilling to fetter himself by an office of this kind. He was for a short time professor of Greek at Oxford. He afterwards travelled through Germany and the Netherlands, and went to Bâle, where he had his works printed by Froben. He died in 1536. His tomb may be seen at Bâle, in the Calvinistic cathedral.-To profound and extensive learning Erasmus joined a refined taste and a delicate wit. Naturally fond of tranquillity and independence, he preferred the pleasures of literary ease and retirement to the pomp of high life. His caution and worldly prudence offended many of the best men of his times. He did great and lasting service to the cause of reviving learning. Although he took no direct part in the reformation, and was reproached by Luther for lukewarmness, he attacked the disorders of monkery and superstition, and every where promoted the cause of truth. He wished for a general ecclesiastical council, to be composed of the most learned and enlightened men, but did not live to see his wish accomplished. He therefore confined his efforts to serve the world by his writings, which will always be prized for their interesting matter and graceful style. The best edition is by Le Clerc, Leyden, 1703, 10 vols. fol. His life has been written by Burigny. Jortin's life of Erasmus is a valuable work. Besides his editions of various classics, and his other philological and theological writings, we will only mention his well known book in praise of folly (Encomium Moria), and his colloquies. His letters are very valuable in reference to the history of that period. ERATO (from ¿páw, I love); one of the muses, whose name signifies loving, or lovely. She has much in common with Terpsichore-the same attributes, the same dress, and frequently a lyre and plectrum. She presides over the songs of lovers, and touches, as Ovid, in his Art of Love, informs us, the hearts of the coldest maidens by her tender lays. (See Muses.) ERATOSTHENES, a learned man in the times of the Ptolemies, born at Cyrene, in Africa, B. C. 275, librarian at Alexandria, improved the science of mathematical geography, which he corrected, enlarged, and reduced to system. He gained his greatest renown by his investigations of the size of the earth. He rendered much service to the science of astronomy, and first observed the obliquity of the ecliptics. (See Ecliptic.) Of his writings, one only remains complete,-Catasterismi,—which treats of the constellations (Schaubach, with a commentary, 1795). Of his geographical works, which were long in high repute, the scattered remains were collected and published by Seidel, 1798. ERCILLA Y ZUNIGA, don Alonzo de; |