weight of oxygen, but the weight of the atoms depends upon that of the standard assumed: thus the weight of an atom of hydrogen being 1, that of oxygen is 8, and phosphorus 12, but an atom of hydrogen being 0-125, oxygen is 1, and phosphorus 1.5.

"When combination takes place between two bodies in various proportions, the numbers indicating the greater are exact simple multiples of that denoting the least. Thus 100 parts of carbon unite with 132, or 265 parts of oxygen, and no other. Again, 100 parts of sulphur unite with 50, or 100, or 150 parts of oxygen; and in the intermediate ones no combination ensues.'

Now it happens that the greatest proportion is sometimes not a multiple, but one-half more than the least; this occurs with respect to iron, of which 28 parts unite with 8 of oxygen to form protoxide, and with 12 to form the peroxide. Again, the exact quantity of oxygen with which 100 of carbon unite are 133 to form oxide of carbon and 266 to form carbonic acid, but there is an intermediate compound, namely, oxalic acid, composed of 100 carbon and 200 oxygen. Once more; 100 of sulphur unite with 125 of oxygen to form hyposulphuric acid, as well as with the three proportions above stated.

In p. 12 we have a marvellously easy method of making sulphuric acid; sulphur "by combustion in atmospheric air over water, unites with oxygen, and forms sulphuric acid." How foolish then have our manufacturers been in using nitre at a vast expense! We must, however, I believe, for sulphuric read sulphurous.

Iodine appears also to have undergone a wonderful change of properties; according to Mr. Topham, it " is abundantly absorbed by water; "the fact is, that water absorbs about 1-7000th of its weight.

In the chapter on the alkalies, potash, soda, and ammonia are mentioned; and after incorrectly stating that the last "next to hydrogen gas, is the lightest known ponderable body," we are informed, that "the other alkalies are lithina, delphine, brucine, vauqueline," and then we are instructed that "the bases of the other alkalies [meaning the four last named], except vauqueline (which is of vegetable origin) have also been formed into amalgams with mercury, and are found to be metallic." From this we might conclude that delphia and brucia are not of vegetable origin, and that the seeds of stavesacre, and the bark of the brucia antidysenterica have been "found to be metallic." The sentence which we have last quoted is followed by "oxygen, therefore, in one proportion is the cause of alkalinity; in another (as will be seen) of oxidation; and in a third of acidity." It is difficult to conceive how so much error could have been crammed into so small a space. If these statements were true, then we may take any substance which is capable of uniting with oxygen; let it be hydrogen, sulphur, or potassium, and by combining them in

different proportions produce a mere oxide, an alkali, or an acid, with the same base. Mr. Topham will find that he has incorrectly stated with respect to different proportions of oxygen, what is true only with regard to different bases. This erroneous view of the case is also contained in the chapter on oxides, in which it is stated that "any simple substance, in union with a less quantity of oxygen than is necessary for the formation of an acid, is termed an oxide." Now acidity does not depend upon the quantity of oxygen, but upon the nature of the base which unites with it. Six parts of carbon combined with 16 of oxygen form an acid, but 6 parts of hydrogen combine with 48 of oxygen to form water. In the next chapter we again meet with the erroneous statement that sulphuric acid is formed by the combustion of sulphur over water; and sulphurous acid is said to be " constituted of 1 atom sulphur and 2 of oxygen in 100." We would inquire whether it is not so constituted in 10, 100, or 1000 parts? or whether its atomic constitution is altered by the quantity subjected to analysis, so that what is true of two portions of 50 parts each added together would not be true of 100 parts?

Nitric acid is said to be a compound of one atom of nitrogen and two of oxygen, instead of five of oxygen; but carbonic acid is one of the most extraordinary we have ever met with: "it is widely diffused through nature, being combined with chalk, limestone, gypsum, magnesia, &c." Of these four statements, one only is correct; chalk and limestone are not combined with carbonic acid, they consist of lime combined with it, and gypsum is neither combined with, nor contains carbonic acid; we need hardly say, that it consists of sulphuric acid and lime.

In speaking of nitrous oxide, it is stated to consist of "two atoms of nitrogen and one of oxygen." We suspect that our author has mistaken volumes for atoms; for this gas, although composed of two volumes of nitrogen and one volume of oxygen gas, is generally allowed to consist of only one atom of each.

It appears from Exp. 4, that our author does not know that nitric oxide and nitrous gas are different names for the same elastic fluid; for he says at p. 64, nitric oxide on coming into contact with atmospheric air receives a further portion of oxygen, and becomes nitrous gas.

We have neither time nor inclination to pursue our observations upon this work any further; and after what we have stated it would be superfluous to offer any additional opinion respecting it; but we cannot refrain from expressing our surprise, that a gentleman who must have distinguished himself in order to have acquired the degree of Master of Arts, should so far have forgotten what was due to his own reputation and to public utility, as to venture to write a book upon a subject, his ignorance of which he must have felt, and all conversant with chemistry must discover.-(P.)

ARTICLE XIII.

Proceedings of Philosophical Societies.

ROYAL SOCIETY.

May 27.-The reading of Mr. Abrahams' paper on Magnetism was concluded; and a paper was read, On the Direction of the Eyes in Portrait Painting; by W. H. Wollaston, MD. VPRS.

June 3.-. Lemon, Esq. was admitted a Fellow of the Society; the name of Charles Macintosh, Esq. ordered to be inserted in its printed lists; and a paper was read, “On the Generation of Fishes; by J. L. Prevost, MD."

The Society then adjourned to June 17, in consequence of the ensuing holidays.

June 17.- Edgeworth, Esq. was admitted a Fellow of the Society, the name of Major Charles Hamilton Smith, ordered to be inserted in its printed lists; and the following papers were read, several of them in an abridged form.

On the Organs of Generation of the Axolotl, and of other Protei; by Sir E. Home, Bart. VPRS.

On the Effects of Temperature on Magnetism and on the diurnal Variation of the Needle; by S. H. Christie, Esq. MA.: communicated by the President.

On the Preservation of the Copper Sheathing of Ships, and on some Chemical Facts connected with it; by the President. On the Application of Doebereiner's new Discovery to Eudiometry; by William Henry, MD. FRS.

The Society then adjourned, over the long vacation, to meet again on the 18th of November next.

LINNEAN SOCIETY.

May 4.-M. G. St. Hilaire was elected a Foreign Member.. A notice from Mr. Wood was read respecting the Golden Oriole, Oriolus Galbula, shot on the 26th of April, flying in company with some Blackbirds, at Aldershot in Hampshire.

The reading was continued of Mr. Vigors's papers on the Natural Affinities of Birds; and of the Catalogue of Norfolk and Suffolk Birds, by the Rev. Messrs. Sheppard and Whitear.

May 24.-On this day, being the birth-day of Linnæus, the Anniversary of the Society was held at one o'clock, in conformity with the Charter, the Right Rev. the Lord Bishop of Carlisle, Vice President, in the Chair.

The following gentlemen were re-elected Officers:

Sir James Edward Smith, President;
Edward Forster, Esq. Treasurer;
Alexander Mac Leay, Esq. Secretary;
Mr. Richard Taylor, Assistant Secretary.

The following were elected to be of the Council for the ensuing year :-Edward Barnard, Esq.; H. T. Colebrooke, Esq.; Major-General T. Hardwicke; Daniel Moore, Esq.; and Philip B. Webb, Esq.

An extensive and interesting series of the various species of Rhubarb from Chelsea Garden was exhibited by Mr. Anderson. The Anniversary Dinner of the Society took place at Freemasons' Tavern, and a considerable number of the Fellows, including many from distant parts of the kingdom, participated in the pleasure of this meeting, which was alloyed only by the absence, owing to indisposition, of their highly esteemed President, whose excellent qualities, great attainments, and invaluable labours for the promotion of science, have long endeared him to those who know him, and especially to the lovers of Natural History. The chair was filled on this occasion by the venerable Prelate, who from the first foundation of the Society has been one of its most zealous supporters.

June 1.-The reading of Mr. Vigors's paper was concluded; and that of Messrs. Sheppard and Whitear's Catalogue continued.

June 15.-The meeting of this evening, which was an extremely numerous one, was honoured by the presence of His Royal Highness the Prince of Saxe-Cobourg, and several other personages of distinction.

The reading was commenced of a paper, On the Structure of the Tunicata; by W. S. Mac Leay, Esq. MA. FLS. and the Society then adjourned, over the summer recess, to meet again on the 2d of November next.

ASTRONOMICAL SOCIETY.

May 14.-The whole of this sitting of the Society was occupied by the reading of the conclusion of Mr. Baily's paper On the Method of determining the Difference of Meridians, by the Culmination of the Moon; this paper having been commenced at the last meeting in April.

The author, after briefly alluding to the nautical methods of determining the longitude, including those by means of chronometers, adverted to five distinct astronomical methods which have been pursued, viz. 1st, By the eclipses of Jupiter's satellites. 2dly, By eclipses of the moon. 3dly, By eclipses of the sun. 4thly, By occultations of the fixed stars. And 5thly, By meridional transits of the moon. The first three of these, by reason of their infrequency and obvious sources of inaccuracy, are of very limited utility; while the fourth method is rendered uncertain from its involving a doubtful datum, the compression of the earth, as well as other difficulties which the author pointed out. He then proceeded to point out that the fifth method was greatly superior to any of the others, in which

opinion he was supported by the testimony of Dr. Maskelyne, Bernoulli, and many eminent astronomers who were quoted. Notwithstanding its high recommendations, this method has not been successfully adopted in practice, and has even led to some awkward anomalies, on account of its having been customary to take the moon's centre reduced to the meridian, and to compare it with the apparent places of stars passing the meridian about the same time in any parallel of declination.

The newly proposed method consists in merely observing with a transit instrument, the differences of right ascension between the border of the moon, and certain fixed stars previously agreed upon, restricting the observations to such stars as differ very little in declination from the moon, and denominated moon culminating stars. The attention of astronomers has been called to this method by M. Nicolai, of Manheim, in several numbers of Schumacher's Nachrichten. It is quite independent of the errors of the Lunar Tables (except so far as the moon's horary motion in AR is concerned). It does not involve the quantity of the earth's compression. It does not require a correct knowledge of the position of the star observed, nor does an error of a few seconds in the clock sensibly affect the result. Hence much trouble is avoided, many causes of error precluded; besides all which, the method is universal.

GEOLOGICAL SOCIETY.

May 21.-The reading of the paper " On the Geology of the Ponza Islands in the Mediterranean; " by George Poulett Scrope, Esq. MGS. was concluded.

The Ponza Islands lie off the coast of Italy, opposite Terracina and Gaieta. They consist of Ponza (anciently Pandataria), Palmarola, and some islets; Ventotiene and San Stefano connect them with Ischia. The harbour of Ponza is excellent. Dolomieu's Memoire sur les Isles Ponces excited curiosity, but is too general to satisfy it. These islands are composed of rocks, of the Trachytic series, and presenting fine sections along their coasts, enabled the author to clear up many doubts and errors which the mere investigations of inland localities have caused to be affixed to this formation.

The Isle of Ponza is long and very narrow, and is eroded by the sea into deep concavities. Harder masses left along its shores show that it once was broader, and protruding ledges mark its former connexion with Quannone and La Gabbia. Prismatic trachyte, variously coloured and disposed, forms the ossature of the island. It is constantly accompanied by, and alternates with, a semi-vitreous trachytic conglomerate, formed of minute pulverulent matter enclosing fragments of trachyte. The prismatic trachyte seems to have been forcibly injected through the conglomerate, and wherever it touches the latter New Series, VOL. VIII.

F