with the saline solution, the temperature of the vapour is the same as that of the solution itself. We understand that Mr. F. has verified M. Gay: Lussac's statement by experiment, and satisfied himself of its accuracy.

II, Index to Kirby and Spence's Entomology.

(To the Editor of the Annals of Philosophy.) DEAR SIR,

Dec. 22, 1822. I beg to submit, through your journal, to the learned authors of the Introduction to Entomology how important an addition to each of their delightful volumes a pretty copious index would be ; and how imperfect their work is without it. It is of course intended that the last volume should comprise all that is necessary in this way; but this is not enough, for during the many years that intervene between the appear. ance of the first and the last volume, the entomological student is deprived of all the advantages of reference, unless he make an index for himself. All the leading facts of the two first volumes may

be

very readily embraced in one index ; and I would suggest to Messrs. Kirby and Spence, that it would be desirable to furnish this assistance to the public without delay, as well as to provide every future volume with an index for itself, with the exception of the last, which will necessarily contain general references for the whole work. I remain, dear Sir, yours sincerely,

NORFOLCIENSIS. III. Separation of Plumbago from Cast-Iron. A curious paper on this subject has appeared in No. 14 of the Edinburgh Philosophical Journal ; the facts related in which we shall proceed to state, and afterwards to offer a few remarks on the theory which has been deduced from them by the writer of the paper, Dr. Mac Culloch.

In the frequent examination of the metal of the iron guns delivered by the contractors to the ordnance, by solution, according to Bergman's suggestion, Dr. M. found that the quantity of plumbago in the metal bore no relation to its strength or goodness, but that the results were sometimes curious, from the very variable quantity which different specimens of the iron contained. The trials were far from confirming the opinion that the worst or weakest metal contained most plumbago; and on one occasion, an exceedingly tough specimen was found to contain a most unusual proportion of this substance, and that in a disengaged state, being visible on breaking the metal; which appeared as if it had been rubbed with powdered black-lead, and left its trace on paper. Where the plumbago was most abundant, the colour of the fracture of the iron was most grey; and Dr. M.'s trials go to prove, in contradiction to the opinion of many iron-founders, that the greyest metal is the toughest. The plumbago was always obtained in the state of powder, and in very small proportion when compared to that obtained from pig-iron.

The same experiments were repeated on the pig-metal used for shells, which is generally distinguished into three kinds; white, grey, and black. All these afforded very large proportions of plumbago, but various in different specimens; the black metal seemed to afford the greatest quantity, but that which was most brilliant and silvery also

investi Pepps

i

Dew my

Que ato burnt ii version

experin these su

yielded it in abundance. In 1807 or 1808, Dr. Mac Culloch was requested to go to a London porter brewery to see an appearance which had very much surprised the people employed in it. They had taken some iron out of their porter backs in making repairs, and had found it, as they said, red-hot. This was found to be an exaggeration; but on removing the iron articles from the porter, they became so hot on scraping off the surface, that it was disagreeable to handle them; while they smoked from the evaporation of the moisture: they were 'cast cones, perforated with holes, and about an inch thick, used as strainers to prevent foreign substances from getting into the pipes, and had been immersed in the porter for many years. On examination, some of them were found to be entirely plumbago ; while in others there was a thick coat of that substance on each side, a little iron only remaining in the middle.

Shortly afterwards, Dr. M. met with the following relation in one of his journeys in the Western Isles. In 1740 an attempt was made to 'weigh one of the Spanish Armada, which had foundered off the coast of Mull; this proved unsuccessful, but some brass and iron-guns were brought up, the former bearing the date 1584. The iron guns were deeply corroded; and on scraping them, it was said that they were found so hot that they could not be touched, and that they did not become cool till they had been two or or three hours exposed to the air.

The following are the general results of Dr. Mạc Culloch's experiments on this subject : l'he blackest pig-metal appears to yield the greatest quantity of plumbago, and in the most solid state. When the experiment is complete, the produce equals the iron in bulk, and is a solid mass capable of being cut by a knife, even into pencils; but as far as has been observed, it is of a much more coarse grain, or scaly granular texture, than natural black-lead. To procure it in perfection, the acid should be very weak, and the operation is then necessarily very tedious. Acetic acid appears to be the best, and it is by this that it is produced in porter-backs in the waste-pipes of breweries, and in calico-printing-houses, where sour paste is employed. If the experiment be perfect, the plumbago becomes hot on exposure to the air, smok

ing while there is any moisture to be evaporated, particularly when the surfaces are scraped off in succession ; there is no apparent difference in the plumbago before and after this operation. When the substance does not heat, on being taken out of the fluid, the whole process of oxygenation appears to have taken place in the solution, probably from an excess of strength in the acid.

From these facts, Dr. Mac Culloch draws the following inferences: that plumbago, by which name he designates the carbon, as it exists in cast-iron, is a metal, and black-lead its oxide: that in white-pig, probably, the combination is this metal and iron; and that in the black it exists in a state of approximation to black-lead: that the operation of the acid is to dissolve the iron, and to oxygenate the plumbago so as to convert it into black-lead : and that if the acid be strong, the whole operation is completed in the solvent; otherwise some additional oxygen is required to produce it in a state of permanence in the air, and that the absorption of this generates the heat in the experiment; Jastly, that the metallic nature of the base of charcoal is also proved from these cts And lest this reasoning should be deemed unsatisfactory, Dr. M. adds the following argument: “ The specific gravity

flange

Secor ence of in vol. Ü gen, and from the ait to the

We ar toes it ne be a mec which is

wean of

:

of pig-iron is about 7'6, and that of black-lead is 2, or less. Now the bulk of black-lead procured in the experiment is equal to thạt.of the original-iron exposed to solution. Two such bodies could not co-exist in the same space, or, if that could be imagined, the specific gravity of such iron must be far more different from that of pure iron than it is. If pure iron indeed is freed from the effects of condensation by heating, it scarcely differs in specific gravity from pig-metal. Thus while we conclude that the plumbago combined with the iron is a metal, we may, also infer that the specific gravity of that metal is not very different from that of iron."

Upon this theory we trust that Dr. Mac Culloch will excuse our offering the following remarks: In the first place, nothing but carbon has been detected in the diamond by the most refined and delicate investigations of chemistry, those of Sir H. Davy, Messrs. Allen and Pepys, and others : that gem, therefore, must be a form of Dr. M.'s new metal; now if black-lead be its oxide, supposing it to contain only one atom of oxygen, then, when equal weights of each substance are burnt in oxygen gas, the former should require, for its complete conversion into carbonic acid, twice as much oxygen as the latter; but the experiments of Messrs. Allen and Pepys have demonstrated, that both these substances require for their combustion precisely the same volume of oxygen.

Secondly, Dr. Mac Culloch does not seem to be aware of the existence of silicium in cast-iron. The experiments of Mr. Daniell, recorded in vol. ii. of the Journal of Science, show that the absorption of oxygen, and the consequent evolution of heat, by the black-lead separated from the metal, is owing to the conversion of silicium into silica, and not to that of any unknown principle into black-lead.

We are not sure that we understand the concluding argument, but does it not indicate, either that Dr. Mac Culloch considers cast-iron to be a mechanical mixture of carbon and the metal, or that he thinks, (which is likewise contrary to the known fact), that the arithmetical mean of the specific gravities of the ingredients of a compound is the true specific gravity of the compound itself?

ARTICLE XII.

NEW SCIENTIFIC BOOKS

PREPARING FOR PUBLICATION,

A Narrative of a Voyage round the World in the Uranie, Capt. Freycinet, dispatched on a Scientific Expedition by the French Government during the Years 1817, 1818, 1819, and 1820; in a Series of Letters to a friend. By J. Arago, Draftsman to the Expedition. The Work will form'a Quarto Volume, embellished with 26 Engravings.

A Description of an Antediluvian Den of Hyænas, discovered at Kirkdale, in Yorkshire, in 1821, and containing the Remains of the Hyæna, Tiger, Bear, Elephant, Rhinoceros, Hippopotamus, and 16 other Animals, all formerly Natives in this country. With a Compa

tative View of many similar Caverns and Dens in England and Ger many: and a Summary Account of the Evidence of diluvian Action afforded by the Forms of Hills and Valleys, and the general Dispersion of Beds of Gravel and Loam, containing similar Bones, over great Part of the Northern Hemisphere. By the Rev. W. Buckland, FRS. FLS. and Professor of Mineralogy and Geology in the University of Oxford. Illustrated by a Map, Views, and Sections of the Caves and Drawings of the Animal Remains.

A Treatise on Navigation and Nautical Astronomy, adapted to Practice and the Purposes of Elementary Instruction. By Mr. Reddle, of the Royal Naval Asylum.

JUST PUBLISHED.

No

Illustrations of the Inquiry respecting Tuberculous Diseases. By John Baron, MD. Physician to the General Infirmary at Gloucester. With coloured Plates. 8vo. 15s.

Lectures on the Structure and Physiology of the Male Urinary and Genital Organs of the Human Body, and on the Nature and Treatment of their Diseases, delivered before the Royal College of Surgeons. By the late James Wilson, FRS &c. 14s.

Journal of an Horticultural Tour through Flanders, Holland, and the North of France. By a Deputation of the Caledonian Horticultural Society, consisting of Mr. Neill, Secretary: Mr. Hay, Planner; and Mr. Macdonald, Chief Gardener at Dalkeith Park. With Plates. 8vo. 16s.

A new View of the Infection of Scarlet Fever, illustrated by Remarks on other contagious Disorders. By W. Carmichael, MD. FRS. Fellow of the College of Physicians, &c. 8vo. 58.

ARTICLE XIII.

NEW PATENTS. J. Witcher, Helmet-row, Old-street, mechanic, M. Pickford, Woodstreet, carrier, and J. Whitbourn, Goswell-street, coachsmith, for an improvement in the construction of wheels.-Sept. 27.

S. Pratt, bond-street, trunk-manufacturer, for improved straps and bands for the better securing of luggage.-- Sept. 27.

T. Binns and J. Binns, Tottenham-court-road, engineers, for improvements in propelling vessels, and in the construction of steam-engines.

Oct. 18.

W. Jones, Bodwellty, Monmouthshire, engineer, for improvement in the manufacturing of iron.--Oct. 18.

S. Wilson, Streatham, Esq. for a new manufacture of worsted. Oct. 18.

U. Lane, jun. Lamb's Conduit-street, straw-hat manufacturer, for an improvement in the platting of straw, and in manufacturing bonnets, &c. therefrom.-Oct. 18.

J. Williams, Cornhill, stationer, for a method to prevent the frequent removal of the pavement and carriage-path, and for laying down and taking up pipes, &c.-Oct. 18.

Ger ction Ersion

Part FLS ford. ringt

d to Adle

By ter.

and eat

and

er;

8.

11th Mon.
Nov. IS W 29.97 29 81 61
2/S
W 30:10 29.81

62
3S

W 30:36|30-10 58
4W W 30•36 30•34|

53
5 W
30-34 30:29

55
W|30 29 30:05

55
7S
W 30.05 30:03

58
8
N 30-07 30.03

52
9N
E 30:07 29.85

53
E 30:35 29:87

52 E 30•35 30:19

50 12 S 30 19.0.01

-56 13N W 30.01 29.55

50 14N W 29.61 29:35

51 de 15 S W 29:43 29:35

51 E 29:71 29:40

44 W 29.72 29:71

51 18 S W 29:95 29.72

55 W 29:90 29:78

56
20 Var. 29 78 29.75

56
21
W 29:98 2978

51
W29 98 29.74

52 W29:99 29.74

52 24 S

W 29:92 29 70 53
25 S

W 29 70 29.68
26 S
W 29•7029.68

55
27 S

W 29.74 29•60 50
28 Var. 29:58 29-46 45.
29 S
W 29:58 29:50

46
30 S
W29:50 29:50

47

The observations in each line of the table apply to a period of twenty-four hours, beginning at 9 A. M. on the day indicated in the first column. A dash denotes that the result is included in the next following observation.