list, by which they are enabled to trace at once the parts of the work which were composed by Dr Leyden. In the two introductory chapters, Mr Murray traces the progress of discovery in Africa from the earliest ages to the commencement of maritime enterprise in modern Europe. In the first book he follows the progress of modern discovery in the interior; in cluding under this head those parts of the coast by which attempts to penetrate inward have been chiefly made, as Congo, and the banks of the Senegal, and Gambia. The se cond book exhibits the discoveries in the maritime countries, beginning with Abyssinia, the chief native power, and making thence the circuit of Africa. The third book, which we consider as peculiarly curious and valuable, is occupied with geographical illustrations and views of the present state of Africa. The author judiciously refrains from indulging in conjectures, which the discoveries of a few years would probably supersede; and rather chooses to exhibit, as a -branch of the history of science, a view of the progress of speculation and

inquiry relative to this continent from the earliest ages. To this part of the work Professor Jameson has contributed a general view of the natural history of Africa, the importance of which cannot fail to be generally recognised. To this book, likewise, are attached historical maps, intended to exhibit the general ideas entertained by geographical inquirers, at these successive periods, of the form and constituent parts of the African continent. The appendix contains translations of some scarce and curious passages of the early geographers, relating to central Africa, which, though often referred to, are seldom accessible to the general reader. For the use of those who may wish to prosecute farther their researches regarding this continent, he has annexed a list of the best works which illustrate its geography. Such is the outline of Mr Murray's plan; into its details we would now gladly enter, but as the space which we could afford to them would be altogether inadequate to their importance, we must deny ourselves that pleasure till our next Number.

Supplement to the Encyclopædia Bri

tannica, Vol. II. Part II. THE present half-volume yields to none of its predecessors, either in the importance of its subjects, or the ability with which they are treated. Even the minor articles of geography and biography evince, in general, consider able extent of research, and skill in condensation and arrangement, and the leading articles fulfil, in their execution, the expectations which the eminent names annexed to them naturally excited.

The first subject of importance which occurs in this Part, is BIBLIOGRAPHY, a branch of knowledge, which, as the author well observes, would be more correctly designated by the word Bibliology. The term originally denoted skill in the perusing and judging of ancient manuscripts, but is now appropriated to the knowledge of books, in reference

to their constituent parts, their editions, and different degrees of rareness, their subjects and classes. The importance of Bibliography is very correctly estimated by the author of this article. While he renounces the extravagant pretensions of some of the French Bibliographers, who represent it as the most extensive and universal of all the sciences; he shews, by an enumeration of its chief objects, that it embraces many curious as well as interesting subjects of inquiry, and is calculated to afford very useful aid to every other species of intellectual Occupation. The business of the bibliographer he states to be, to trace the history of books in regard to their forms and all other constituents, and, consequently, to trace the beginnings and progress of typography; to mark the differences of editions, and to indicate that edition of every book, which is esteemed the most correct

and valuable; in the case of books published anonymously, or under feigned names, to assign those names, which the discoveries of literary history may have brought to light; to collect all remarkable facts attaching to the history of books, such as the number of their editions, their rareness, their having been condemned to the flames, or suppressed, and to furnish catalogues of the books which have appeared in the various branches of knowledge. The plan which he proposes is, to point out the progress and best sources of information in regard to all those departments of Bibliographical knowledge; and in conformity with this plan, he divides the subject into the following heads: 1. Of the constituent parts of books, and the differences of editions; 2. Of early printed books; 3. Of rare books; 4. Of the classics; 5. Of anonymous and pseudonymous books; 6. Of condemned and prohibited books; 7. Of bibliographical dictionaries and catalogues; 8. Of the classification of books; 9. Of Bibliography in general. Under these heads the author displays an accurate and extensive acquaintance with his subject, and communicates much information, particularly with respect to the books proper to be consulted in the various departments of Bibliography, which cannot fail to be extremely useful to those who wish to pursue this curious line of inquiry. In treating of the first head, the author has refrained, perhaps too scrupulously, from entering into any detail in regard to the various substances used for writing, before the important art of making paper from linen rags had been discovered. He has rendered, however, a greater service to the student of Bibliography, by referring him to the most approved works on this branch of the subject, viz. Horne's Introduction to Bibliography; Nouveau Traité de Diplomatique, Tom. I.; and Mr Peignot's Essai sur l'histoire du Parchemin, et du Velin, in the introduction to which is given a complete list of separate works on this subject. He next adverts to the different kinds of writing peculiar to different ages; and on this interesting branch of Bibliography, the books which he recommends are the Nouveau Traité mentioned above, and, in particular, Astle's Origin and Progress of Writing. The

office of Transcribers, persons employed to copy books before the inven tion of printing, next claims attention, and the evils which arose out of their ignorance and carelessness. Petrarch, who flourished in the fourteenth century, complains of these evils in the following remarkable terms: "How shall we find a remedy for those mischiefs which the ignorance and inattention of the copyists inflict upon us? It is wholly owing to these causes that many men of genius keep their most valuable pieces unpublished, so that they never see the light. Were Cicero, Livy, or Pliny, to rise from the dead, they would scarcely be able to recognise their own writings. In every page they would have occasion to exclaim against the ignorance and the corruptions of these barbarous transcribers." On the invention of printing, these copyists were naturally alarmed by an art which threatened to deprive them of employment, and they endeavoured to obtain from their respective governments, the exclusive privilege of multiplying copies of books: but the new art was too evidently beneficial to the interests of literature to be repressed by their machinations.

The obscurity which hangs over the inventor of this admirable art, and over the place of its origin, is one of the most curious facts in the history of Bibliography. Numberless dis cussions have taken place on this subject, and the public opinion is still undecided. Were the question to be determined by numbers, the laurel must be placed on the brow of Guttenberg of Mentz; though champions of great ability maintain very keenly the pretensions of Laurence Coster of Haerlem. Declining to give an opinion in a case of so much uncertainty, our author contents himself with referring to the following works in which the question is agitated :Mallinkrot, De ortu et progressu artis Typographica, published in 1640; Daunou's Analysis of the various opinions on this subject, published in the fourth volume of the Memoirs of the Moral and Political Class of the French Institute; Monumenta Typographica of Wolfius; Meerman's Origines Typographica Prosper Marchand Histoire de l'origine et des premiers progres de l'Imprimerie; a Supplement to which was published by Mercier,

Abbé de St Leger; Lambinet's Recherches, historiques, litteraires, et critiques sur l'Origine de l'Imprimerie; M. Serna Santander's Essai Historique, prefixed to his Dictionnaire Bibliographique Lichtenberger's Initia Typographica and Ottley's Inquiry into the Origin and early History of Engraving.

The establishment and progress of printing, in particular countries and places, is likewise an object of curiosity to the Bibliographer. The books which our author recommends on this subject are Ames's Typographical Antiquities, which contains memoirs of the early English printers, with a register of their publications from 1471 to 1600. It was first published in 1749, in one volume quarto; a second edition, enlarged by Mr Herbert to three volumes quarto, appeared in 1790; and a third, illustrated with superb embellishments, and containing some valuable additions by Mr Dibdin, is now in course of publication. For an account of the typographical histories of France, Germany, and Italy, we are referred to Peignot's Repertoire Bibliographique Universel.

The next thing mentioned, as requisite to the Bibliographer, is a knowJedge of the different classes and bodies of letters used by printers, and of the corresponding appellations assigned to the different bodies by printers of different countries. The books recommended on these points are Stower's Printer's Grammar, and Fournier's Manuel Typographique.

In treating of the forms of books, our author very briefly adverts to the method practised among the ancients, of rolling up their books on a cylinder of wood, to the ends of which nobs or balls were affixed, often richly or namented. In the present article, the attention of the author is chiefly directed to the various forms in which books have appeared since the origin of printing; from an imperfect knowledge of which, essential errors have arisen with regard to particular editions. The circumstance from which these mistakes generally proceed is, that different sizes of paper are comprehended under the same name. A test is afforded by the water-lines in the sheets, as, in folio and octavo sizes, they are uniformly perpendicu lar, and horizontal in quartos and duo

VOL. I.

decimos. Some useful remarks are given with regard to the particulars which may give one edition of a book a preference to another.

Under the second head, a description is given of the books which, in the first rude efforts at printing, were impressed with solid wooden blocks. The editio princeps of the Bible, printed at Mentz between the years 145055, was the first book of any considerable magnitude, printed with moveable metallic types. On the subject of early printed books, the following works are recommended; Laire's Index librorum ab inventa typographia ad annum 1500, cum notis; Santander's Dictionnaire Bibliographique choisi du quinzieme siecle; Bibliotheca Spenceriana, a descriptive catalogue of the books published in the fifteenth century in the library of Earl Spencer, by Dibdin; Maittaire's Annales Typographici ab Artis inventæ origine; Annales Typographici ab Artis invento origine, ad annum 1500, post Maittaire, Denisii, aliorumque emendati, et aucti; Opera S. W. Pauzer. We regret that our limits will not permit us to follow the learned author through the instructive details into which he enters on the remaining branches of his subject.

Upon the whole, we consider this as the most judicious and enlightened treatise that we have had the good fortune to meet with on the subject of Bibliography.

The article BILLS OF MORTALITY displays a perfect knowledge of the subject. The author, Mr Joshua Milne, Actuary to the Sun Life Assurance Society, has already distinguished himself by his masterly Treatise on Annuities and Assurances, and his si tuation and habits of inquiry furnish the best security for the correctness of his views, and the accuracy of his information on the subject of the present article. The plan which he lays down, and which he follows out with great ability, is, " to give a brief his tory of the principal things that have been done in this way;-to notice some of the principal mortuary registers, and enumerations of the people;-to point out some of the prin cipal defects in most of the published registers and enumerations ;-and lastly, to submit some forms, according to which, if enumerations be made, and registers kept, they will be easily

H

convertible to useful purposes." The conclusion of the article, which contains these forms, we would recommend as particularly worthy the attention of all, who, either from interest or curiosity, are desirous of obtaining regular data for determining the law of human mortality.

Under the article BLASTING will be found a minute and accurate account of the method employed by quarriers and miners in blasting asunder rocks by the force of gunpowder. We are happy to observe, that the author, whose opportunities of observation are such as few individuals can boast, recommends the practice of wadding with sand as equally efficient with the common method, while it exposes the workmen to much less personal risk.

The articles BLEACHING, BREWING, and BRICK-MAKING, are contributed by a gentleman, who, if he has been excelled by another chemist in the brilliancy and success of his experiments, is second to none in a profound knowledge of chemical science; while his extensive attainments would have raised him to eminence in any department of philosophy or literature. The departure of this gentleman from Edinburgh we have ever regretted as a serious loss to the lovers of science in this city; though we trust it has been of advantage to himself,-as, by extending his labours over a wider sphere, it has materially advanced the general interests of learning. Of his indefatigable exertions in the pursuit of truth, we have two very remarkable instances towards the commencement of the article BLEACHING. Mr Parkes, in his essay on Bleaching, (Chemical Essays, Vol. IV.) affirms, that it is stated by Theophrastus, that lime was used by the ancients in bleaching; and that a ship, partly loaded with linen, and partly with water for bleaching it, was destroyed by the accidental access of water to the lime. "We endeavoured, with some pains," says Dr Thomson, 66 to verify this quotation; and for this purpose, turned over all the writings of Theophrastus with which we are acquainted, without being able to find any thing bearing the least allusion to it. We have doubts whether lime could be employed as a detergent of linen, without injuring the texture of the

cloth, and, on that account, it would have gratified us exceedingly to have found such a statement in so respectable and correct a writer as Theophrastus." It is well known, that the first important improvement made in the process of bleaching in this country, was the substitution of water, acidulated with sulphuric acid, in place of the buttermilk previously employed. Some years after, in consequence of the experiments which had been made by Scheele on manganese, mixed with muriatic acid, a new modification of that acid was discovered, which possessed the property of destroying vegetable colours. To this substance, Scheele gave the name of dephlogisticated muriatic acid. Berthollet, who, in 1785, repeated the experiments of Scheele, discovered that this substance was a compound of muriatic acid and oxygen. He, therefore, gave it the name of oxygenated muriatic acid, which was afterwards shortened into oxymuriatic acid, the appellation by which it is still known among bleachers. Its property of destroying vegetable colours led Berthollet to suspect that this acid might be introduced with advantage into the art of bleaching, the process of which it would greatly shorten. In April 1785, he read a paper on this acid before the Academy of Sciences at Paris, in which he mentions, that he had tried the effect of the acid in bleaching cloth, and found that it answered completely. The following year, he exhibited the experiment before Mr Watt, who, on returning to England, commenced a practical examination on the subject, and was, accordingly, the person who first introduced the new method of bleaching into Great Britain. Yet Mr Parkes, in the essay before mentioned, states, that in the early part of the year 1787, Professor Copland of Aberdeen accompanied the present Duke of Gordon to Geneva, and was shown by M. de Saussure the dissolving pro perty of oxymuriatic acid. Struck with the importance of the experiment, Mr Copland, on his return to Aberdeen, in July 1787, repeated it before some eminent bleachers in his neighbourhood. These gentlemen were Messrs Mylne, of the house of Gordon, Barron, and Company, A berdeen. They immediately began the application of the process to the

bleaching of linen on a great scale; and Mr Parkes assures us, that they were the first persons. To be enabled to decide with certainty on these rival claims, Dr Thomson applied to Mr Watt himself. Fortunately, that gentleman had preserved copies of all his letters since 1782, taken by means of his copying machine. Dr Thomson being allowed to peruse all such as bore any reference to the subject in question, found two which set the matter at rest. The one, dated March 19, 1787, is to his fatherin-law, Mr Macgregor, and contains a particular detail of the new bleaching process, states its advantages, and says that he had sent to Mr Macgregor a quantity of the whitening liquor. In the other, addressed to Berthollet, and dated May 9, 1787, he mentioned the proportion of acid and alkali which he employed, and the process which he followed in preparing the cloth. As the date of both these letters is some months prior to Mr Copland's return from the Continent, it is clear that Saussure has no claim to the original discovery, nor Mr Copland to the first introduction of the new process into Great Britain.

These two instances may serve to prove Dr Thomson's industry in collecting facts for the purpose of ascer taining the truth; indeed, it is impos sible to conceive any thing more truly philosophical than the spirit with which all his investigations are conducted. We cannot now follow him through this and the other articles which bear his signature, but must content ourselves with giving a hasty sketch of the plan which he pursues in each. In the commencement of the article Bleaching, he states that his business is merely to supply the defects of the article in the Encyclopadia. These are chiefly two; 1. A very incomplete historical detail of the improvements in bleaching, at least as far as this country is concerned. 2. The omission of any description of the present mode of bleaching, as practised by the most enlightened manufacturers of Great Britain. After a very clear account of the progress of the new method of bleaching in this country, Dr Thomson mentions the ingredients from which the oxymu riatic acid is obtained, and the proportions of these ingredients recommend

ed by different persons. The propor tions which he himself recommends as the most economical and advanta geous are, 2 parts sulphuric acid, 2 parts, water, 1 part common salt, and 1 part black oxide of manganese. Hé next proceeds to describe the present methods employed in the bleaching of linen, the bleaching of cotton, and the bleaching of rags for the papermaker; for all of which we must refer our readers to the article itself, which will fully satisfy their curiosity.

The article BREWING we consider particularly valuable; it is indeed the only satisfactory account of that im portant art which has hitherto been published. The author divides it in to five chapters. In the first he gives a short history of the art; in the se cond he gives an account of the dif ferent kinds of grain employed in brewing, and terminates the chapter by a table, exhibiting the most re markable properties of a considerable number of specimens of British barley and big, as determined by his own ob servations; in the third he treats of the process of malting,-and to this chapter likewise he subjoins two va luable tables, which exhibit, in one view, the result of a considerable number of trials which he made on malting different varieties of grain; in the fourth chapter he treats of brewing,→→ terminating this chapter too with a table, exhibiting the results obtained by brewing with malt made from a considerable number of different va rieties of barley and big; in the fifth chapter he gives an account of the na ture and properties of the different kinds of ale and beer manufactured by the brewer,-here, again, we are presented with a table, exhibiting the quantity of porter brewed by the thir teen principal houses in London dur ing the last nine years, and thus giv ing an accurate conception of the extent to which the porter trade is car ried on in the metropolis. The explanation of plates subjoined to the whole contains a description of the vessels used in a London porter brew ery.

In the article BRICK-MAKING, he begins, as usual, with a short history of the art; he then mentions the na ture and kinds of clay employed, next, the preparation of the clay, and formation of the brick; then the burning. Under the last head, he