it would no longer be true, that *❝time, while it confirms the dictates of nature, destroys the fictions of opinion."

But nothing has a more powerful tendency to produce those erroneous judgments, which occasion diversity of opinion, than the predominancy of passion over reason. While the mind is kept perfectly cool, and free from agitation, it can contemplate objects according to their real nature, without exaggeration or distortion: and to view every thing as it is in itself, and as it stands related to other things, is the proper office of the understanding, and the only way to discover truth. In mathematical and philosophical reasonings, provided the feelings of vanity and emulation be excluded, the understanding is commonly free from the bias of passions, and pursues truth in the right line of fair investigation. But on other subjects, in which personal interest is concerned, and concerning which, hope, fear, or any other powerful pas sion renders the decison, on either side, an object of desire or aver sion, we are in perpetual danger of forming false judgments. It is not, indeed, certain, that in determining any doubtful question, in the manner which best accords with our private advantage, we are adopting an error; for it may happen, that speculative truth and personal interest may coincide: "People," says Mr. Locke, "may stumble upon truth in the way to preferment." But in cases in which the inquirer is deeply concerned in the result of his speculations; when, for example, wealth, popularity, or advancement, is connected with one decision, and poverty, obscurity, or suffering with the reverse, it requires no small portion of integrity and fairness, to make an impartial judgment. It cannot admit of a doubt, that the edifice of superstition has lasted longer, by

Opinionum commenta delet dies,

Natura judicia confirmat.

means of the buttresses which pow. er has erected to support it, than it could have done without them. Many opinions are now existing, and even flourishing, through their alliance with interest, which, left to the natural process of the hu man intellect, would probably, by this time have been extinct.

The moral causes of diversity of opinion, already enumerated, may be sufficient to account for innumerable cases of erroneous judgment, in which men wander, in various directions, from the truth, merely because they are not honestly and resolutely engaged in the pursuit of nowledge. Other causes, less under our controul, remain to be mentioned.

Great confusion of ideas, and consequent diversity of opinion, arise from the want of precision in the use of terms. The only science in which the leading term is accurately defined, and strictly used in one given sense, is mathematics; and to this cause is, in a great measure, owing the superiority of this science to all others, in perspicuity and certainty.

As far as the science of physics partakes of mathematical accuracy, in its use of terms, it becomes capable of demonstration; and just in the degree in which, from the want of a complete idea of the things or properties which the terms express, they are imperfectly defined, uncertainty arises. In other sciences, particularly metaphysics, theology, and morals, innumerable terms are adopted, which in different connections, and used by different persons, represent different combinations of ideas. Hence when they are employed in argument, a confusion of conception, and diversity of opinion, are necessarily produced. The whole metaphysical doctrine of Aristotle, concerning being abstractedly considered, is a mere science of words; and the innumerable disputes which it created among the scholastics in the middle age, were nothing better than logomachies. The sects

of the nominalists and realists, which through the eleventh and twelfth centuries, disturbed the worlds with angry contentions on the question, whether the universals have a real essence, or are mere names, would have been at once annihilated by settling the meaning of the terms genus and species. Confusion in the use of the terms substance, nature, being, person, generation, &c. gave rise to the numerous sects in which the christian church was early divided, concerning the divine nature and person of Christ. The ancient schools of the philosophers, maintained endless disputes concerning the supreme good, the value of pleasure, and other moral topics, which originated entirely, in the different collections of ideas which they respectively connected with the same words. "Let us," says Cicero, to the Stoic, "settle the meaning of terms, and no controversy will remain." Among disputants of modern times, greater precision of language has been studied; yet, perhaps, it will be found, that the controversies concerning liberty and necessity, concerning the foundation of morals, and some others, are rather disputes about words than things.

Disagreement in judgment, and, consequently, diversity of opinion, is further increased by the injudicious use of metaphorical language. Figures of speech are the instruments of oratory, not of logic. By distracting the mind between different objects, they interrupt that steady contemplation of the matter in question, which is necessary to the discovery of truth. They are also frequently employed to create arbitrary associations, and to prepossess the mind by impressions on the imagination, while the understanding ought to be coolly occupied in argumentative discussion. this, almost every treatise in theo

Of

• Conferam tecum quam cuique verbo rem subjicias nulla erit controver sia. DE FIN. 1. iv. c. 27.

logical or political controversy furnishes examples. This is often to be imputed to crafty design, but is sometimes merely the effect of literary vanity. Writers who excel more in fancy than judgment, and whose taste in style inclines rather to ornament than simplicity, are too apt to load even scientific disquisitions with rhetorical figures and thus lose in perspicuity of reasoning, more than they gain in elegance of writing. It may deserve the attention of those who are fond of eloquent argumentation, that one of the most perfect books of reasoning in the world, the Elements of Euclid, has not a single rhetorical figure from the beginning to the end. As far as language is concerned in argument, a better rule cannot be laid down, than that of Cicero: "Care should be taken to make use of the most common words, and such as are best adapted to express the meaning*."

The neglect of method in study, is another fruitful cause of diversity of opinion. Even in the construction of general plans of education for public schools, much remains to be done, before a regular edifice of instruction will be erected. There is a natural connection among the several parts of science, which renders it exceedingly desirable that a broad foundation being laid in the knowledge of the materials and the instruments of science, things, and words, the superstructure should be raised with a due regard to relation, proportion, and harmony. When this great work shall be accomplished, by the united exertions of well-informed and comprehensive minds, it may be expected, that many systems of opinions will be overturned, and that the uniformity of judgment, which statesmen and priests have so long in vain attempted to produce by coercion,

will in some degree arise from the regular investigation of truth. For the want of such a plan of instruction, knowledge, even upon the subjects most interesting to man, is commonly gathered up in an accidental and desultory manner. Partial views are taken of great questions in theology, morals, and policy; no single point is examined throughout, and in regular train. A few arguments, on one side, are contemplated in full view, and in a strong light; others of equal importance are slightly noticed; and, perhaps, the whole, or the greater part of the evidence, on the side contrary to that which the reader is disposed to favour, is overlooked, or designedly kept out of sight. The inevitable effects must be prejudice, error, and diversity of opi

nion.

If the matter be traced still higher. it will be found that, where neither passion nor prejudice, interferes, men still think differently, from the want of certain data, in which they are agreed, as the basis of their subsequent reasonings. Excepting only in pure geometry, a foundation of definition and axioms has never yet been so firmly laid as to produce, in the application, irresistible demonstration. Some philosophers have conceived, that there are in every science certain first principles, the truth of which is intuitively perceived. But it is a strong presumption against the existence of such principles, that no one has ever been able to discover a criterion by which they are to be distinguished, on the one hand, from opinions formed by prejudice, and, on the other, from the legitimate deductions of reason. It will perhaps be found, upon strict examination, that those first principles which are called axioms in geometry, appear to the mind as certain truths, because they necessarily follow from the admitted signification of the terms. The whole is known to be greater than its part, not by intuitive reason, but, because the terms whole and part, be

ing understood to express certain relative ideas of magnitude, cannot retain their meaning, unless the proposition be received as true. If this explanation of the nature of an axiom be accurate, the reason why there is such a perfect agreement concerning geometrical truths, and so much diversity of opinions concerning propositions in other sciences, is, that, in the former case, the leading terms which are made use of are universally understood in the same sense; but, in the latter, have different meanings.

Diversity of opinion must be ultimately ascribed to the different degrees of imperfection in human knowledge. Were all men perfectly acquainted with the nature, properties, and relations of the beings which come under their perception or contemplation, they must see every thing as it is, and must, therefore, form the same judgment concerning it. Did all men know alike, though imperfectly, their opinions must be the same. But, while one man knows more than another, and while men, from their incomplete knowledge of things, must necessarily view the same objects under different aspects, and be liable to misconception and error, it is impossible that diversity of opinion should not arise. Concerning mathematical figures and quantities, our knowledge is certain. Concerning the forms and obvious properties of bodies, which come under the notice of the senses, the judgments of different persons will commonly be the same. Concerning physical powers, the effects of which are subjected to experiment, a general agreement may be expected. But, with respect to historical facts, which must be reported on human testimony, and cannot be judged of without weighing various circumstances; with respect to moral and political questions, the accurate decision of which requires a diligent examination of numerous facts; and with respect to intellectual beings, and their powers and their qualities,

known only from inference or analogy, opinions, however satisfactory, must be liable to great diversity. On on these latter subjects, as one has well observed*, it is diffi cult to find out truth, because it is in such considerable proportions scattered in a mass of opiniative uncertainties, like the silver in Hiero's crown of gold.

Error and its inseparabie concomitant, diversity of opinion, are entailed by an irreversible decree upon human nature. These defects may, however, be in some measure corrected. Without the aid of persecution, which can at most only enforce an hypocritical uniformity of profession, instead of unity of belief, the liberal protection and encouragement of free inquiry may cherish the love of truth, and promote the honest and ardent pursuit of knowledge. Individual attention to moral discipline may cure those diseases of the mind, which multiply and perpetuate erroneous opinions. If the project of an universal philosophical character, in which the present ambiguities of language should be avoided, and all the varieties of human ideas should be correctly represented, and classically arranged, be too difficult to be accomplished, men may, at least, learn to use with greater caution and skill, the symbols with which they are already furnished. New institutions of education adapted to the present state of knowledge, may be introduced, in the room of the cumbrous systems, which time has fairly worn out. Unprofitable speculations may give way to such literary and scientific pursuits, as promise general utility. And if, after all, knowledge should never become so perfect and universal, as to banish diversity of opinion, men may, at least, be heartily united in prosecuting the great object of the common good, and, with respect to every point of doubtful speculation, may candidly agree to differ.

• Glanville.

CHEMICAL EXPERIMENTS AND OBSERVATIONS ON THE EXTRACTION OF SUGAR AND SYRUP FROM INDIGENOUS PLANTS....HERMSTÆDT.

FROM the chemical analysis of vegetable substances, and the knowledge of their constituent and other particles contained and mixed with them, it is sufficiently evident that the East and West-Indies are not the only countries provided by nature with saccharine plants; but saccharine matter is abundantly found in other productions of the vegetable kingdom, and it only requires an assiduous examination to point out those vegetables from which it may be most copiously and in the least expensive way obtained.

Among the plants hitherto examined, none deserve to be ranked so near the true sugarcane as the whole genus of maple trees, and of these, particularly the sugar and silver maple, Acer saccharinum, and A. Dasycare pon Ehrh: Both trees have been used for these fifty years, to obtain sugar from them, which in the last years has proved to be particularly profitable. By my own experiments, which I have repeatedly made since the winter of 1796, I found out, that from all species of maples, sugar may be, with more or less profit, obtained; and that the sugar and silver maples, growing even in Germany, though not in the best soil, give a very good raw sugar, not inferior to the best West-India cane sugar, and which is got so cheap, that a pound of it will come no higher than eighteen or twenty pfennige, or about two pence half-penny, and only a groshen or a penny, when instead of charcoal common coal or turf are employed for boiling the juice, and particularly when the operation is made upon a large scale, as one labourer is able to attend five hundred trees during the period of tapping them. The process of boiling the juice is besides so very simple,

that every body may soon learn it. But these advantages are only to be expected from the sugar and silver maple, as the other species, Acer Negundo, A. campestre, A. platanoides, and A. pseudoplatanus, contain a less quantity of juice, which is also not so rich in saccharine matter. However, as plantations of those maples require a space of twenty or twenty-five years before the trees are large enough to admit tapping, it will be not improper, but of great utility to the communinity, to examine, meanwhile, those indigenous plants, from which like wise a useful substitute for the WestIndia sugar may be extracted; and it is with this view I have made the following experiments:

a stone mortar, the juice was expressed, which weighed three pounds. This juice, whose sweetish taste had still a disagreeable flavour of herbs, was clarified with the white of eggs, after which that taste was scarcely perceptible; and being thickened to the consistence of a syrup, eight ounces of a very agreeable tasting syrup were obtained.

Examination of the Spikes of IndiaCorn.

As the young spikes, when they are beginning to form, possess a very agreeable saccharine taste, they were thought fit for being examined. Ten pounds of them were accordingly squeezed in a stone mortar, and the juice expressed, after the leaves had been stripped

India-Corn.

India-Corn (Zea Mays) is said to contain, according to Von Justi, sugar, particularly in the nodes of the young stalks, from which Mr. Jacquin, of Vienna, has successfully prepared it; and this is farther confirmed by Mr. Marabelli, in a dissertation on the subject. It is likewise reported, that the extraction of the sugar from the stalks of Indiacorn, growing particularly in a marshy soil, has been tried in Italy upon a large scale, but afterwards left off again, as it was found not to answer the purpose, the sugar thus obtained being more expensive than common raw sugar. To be convinced by my own experience, on this subject, I made some experiments, of which the following are the results: A quantity of India-corn was cultivated in a tolerable, and somewhat marshy soil, for the purpose: when the young plants were about six inches high, the leaves, when chewed, had a sweetish taste, but the stalks, particularly about the nodes, tasted quite like sugar. These young plants being cut off as near the ground as possible, freed from the leaves, and sufficiently cleaned; ten pounds of them were cut in pieces, and, being pounded in

milky juice, which could not be rendered perfectly clear by the white of eggs. By a slow evaporation to the consistence of a syrup, nine ounces of a brown agreeable tasting syrup were got, but which differed from the former by being more mucilaginous.

Examination of Stalks of Indiacorn, of a more advanced growth.

Twenty pounds of these stalks were cut in pieces, and with the addition of water, squeezed in a stone mortar, and the juice expressed, which possessed a disagreeable and somewhat acrid taste. Being in the same manner thickened to the consistence of a syrup, twelve ounces of syrup were obtained, which had a disagreeable saline taste, and might rather be considered as a vegetable extract, than as sugar.

Experiments far obtaining Dry

Sugar from India-Corn.

To learn, whether it was possible to exhibit a crystallisible sugar from this plant, the syrups prepared from the young stalks and the spikes were each dissolved by itself in fresh lime-water, and gently boiled, by which a great part of their impuri