dew more abundant, but no dew will fall if they are both poffeffed of the fame power, and in the fame degree. It is known that the dew does not fall with the fame facility upon all bodies, and that electric bodies are thofe on which it falls with the greatest abundance. This fact admits of an eafy explanation, if we fuppofe electricity to be the cause of the dew; for the electric bodies do not readily receive electricity from the medium which furrounds them; there is, therefore, always a greater difference between the electricity of the air and that of the electrics which are placed in it, than between the electricity of the air and the conducting bodies which it envelopes. Now it is in the ratio of this difference that the power of electric attraction acts, and confequently these bodies ought to be covered more abundantly with dew.

As electricity is often, if not always, the caufe of dew, no one will doubt the neceffity of attending to it in the botanical meteorology, as every one is acquainted with the influence of dew on the growth of vegetables.

In the Phil. Tranf. for 1773, are obfervations on the electricity of fogs, which prove that they are generally electrical. Mr. Achard has made feveral obfervations, the refults of which correspond entirely with thofe, for he conftantly found that the air was more or lefs electrified by a fog. Twice he observed, that in the space of a few minutes the fog ceafed altogether, and fell in form of a fine rain; and though it was very thick, difappeared in about feven minutes. It is alfo very probable that rain is occafioned by electricity; and of this we fhall be convinced, if we confider the attractions and repulfions that the terreftrial or atmospheric electricity muft occafion, as well between the furface of the globe and the vapours contained in the air, as between the particles of vapour which always neceffarily tend to difperfe, or unite the aqueous particles which swim in the atmosphere, and to bring them nearer, or carry them farther from, the earth.'

We wish alfo to transcribe the obfervations of the fame author on the analogy between electricity and heat; but they. are too long, and we must alfo allow that they are in fome, degree incomplete. The effects of electrical fire on metals and on air, may be added in fupport of Mr. Achard's pofition; and it is probable that, from the fimple luminous effect of phosphoric bodies, to the fufion of metals by lightning, the whole may be refolved into different modes of decompofition, or more properly of the efcape of phlogiston. The progress of fcience is better affifted by extending the influence of known principles, than inventing new ones; for the farther we advance, the more clearly we perceive, that the operations of nature are equally fimple and extenfive. We fee but one link of the chain; yet we fee that it extends from earth to heaven. Though

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Though its purpofes are innumerable, and its influence boundless, the means by which they are executed as much excite our admiration when known, as they did our astonishment while we remained ignorant of them.

Mr. Adams's obfervations on medical electricity deserve more attention, as they are profeffedly the abftract of a system, • formed on the experiments of the last four years.' We shall therefore infert them.

In this fyftem, it is ranked as an antifpafmodic, is confidered as the most powerful external application to diseases, and, from the various manners in which it is used, ferves the purposes of a fedative, a ftimulant, and a deobftruent. In medicine, it becomes then applicable to palfies, rheumatisms, intermittents, to fpafm, obftruction, and inflammation. In furgery it has confiderable fcope for action; where contractions and fprains, tumors, particularly of the glandular fort, wafting of the mufcles, and other incidents, form a catalogue of vifible difeafes, as diftreffing to the fight of others as to the patients themfelves. The gout, and the fcrophula, or king's evil, two diseases which have tormented mankind, and been the disgrace of medicine to the prefent time, are ranked among those to which this remedy is applicable; and in the commencement of the complaints, I am informed, has been wonderfully fuccefsful. To remove ill-placed fits of the gout, it should seem to be a more rational application than any medicine, for it applies directly to the feat of the disease, with a power and rapidity unknown in phyfic, and perfectly manageable at difcretion; and, as it is a remedy which applies to the understanding as well as to the feelings, I fhould think it better worth the attention and contemplation of men of liberal education, than the compounding a medicine, in which they place little faith, or applying a plaifter, in which they have none at all.'

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After much trial of this remedy, we cannot be fo fanguine in our recommendations. We are at least certain that it is not a fpecific, as our author fuppofes, in the complaints for which it was recommended by Mr. Birch. Electricity, though conducted with the greatest attention, has more frequently failed than fucceeded in fimilar cafes. But we fhall referve our remarks on this fubject, because we have some reason to expect the fyftem at large, which we shall examine with candour and impartiality.

The Effay on Magnetism is concise, clear, and inftructive. We fhould have extracted a part of it, but that we wish to avoid repeating what is already known; and the few novelties. are intimately mixed with the obfervations of others. The whole is however advantageoufly related, and deserves our ommen dations.

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Outlines of the Theory and Practice of Midwifery. By Alexander Hamilton, M.D. F.R.S. Edin. 8vo. 5s. in Boards. Robinson. THOUGH we do not in general approve of thofe literary

impofitions, where a fecond edition is published with a new title, yet in some cases it is not only defenfible, but even commendable. The prefent work was published in 1775; it was then lefs accurate than we expected to find it, and less full than even a fyllabus probably should have been. In the interval our author, whofe reputation and importance feem by his titles to have increased, has not been inattentive to his firft offspring, but has revised and amended it in fo many places, that it is really become, as he observes, a new work; and as it is different in matter' it ought to differ in form.' We readily admit his apology; and think, both in justice to himself and the world, who, as well as ourselves, might have overlooked it, that he has acted with propriety and prudence. We have therefore again perused it, as a new treatise; for though we at first attempted to mark the changes and amendments, they foon grew too numerous for our attention. In its present state, we think it an impartial and judicious account of midwifery, with its more recent improvements. Its principles are more fcientific than thofe of the former work, and its different parts connected with more skill. The pathology is comprehenfive and accurate; the practice clear and enlightened. It is not eafy to produce a proper specimen from a performance of this kind; but we have inferted the following extract, because it affords, in our opinion, important information, together with a very ingenious explanation.

In the longitudinal contraction of the uterus, when an arm prefents, and the shoulder is advanced in the paffage, fo that the feet cannot eafily be come at, Dr. Denman advises "to pull the body lower down by the arm, and the difficulty will be leffened or removed." "There is, happily, (he adds), no neceffity of turning the child in thefe circumftances; for it will be born by the effect of the powers of nature only. In fuch cafes the child does not come double, but the breech is the first part delivered, and the head the laft, the body turning upon its own axis."

'He adopts this opinion from four cafes which occurred in his own practice, and several fimilar hiftories related by others; in all which, however, the child was dead. He therefore infers, "That, in cafes in which children prefent with the arm, women would not neceffarily die undelivered, though they were not affifted by art."

He concludes his obfervations with this important remark.

"The benefit we are to derive in practice from the knowledge of this fact is, that the cuftom of turning and delivering by the feet, in presentations of the arm, will remain neceffary and proper in all cafes in which the operation can be performed with fafety to the mother, and give a chance of preferving the life of the child; but, when the child is dead, and when we have no other view, but merely to extract the child, to remove the danger thence arifing to the mother, it is of great importance to know, that the child may be turned fpontaneously by the action of the uterus."

• Dr. Denman's remark is new to me. In a cafe where the powers of nature have been usually confidered as defperate, it is new, perhaps, only because the practitioner has thought it ufelefs to wait for them. But though curious, as it fhews what nature in her ftruggles can perform; and though furprifing, as it apparently contradicts the laws of motion; it' feems to me unneceffary, as in the numerous arm-prefentations which I have attended, the child has for the most part been preferved, and the woman has feldom fuffered any ma terial injury from the delivery. I have therefore continued to practise the method which I have juft recommended; and, in the most intricate presentations, have generally fucceeded in making the delivery, by fixing a fillet on the arm, and altering the pofition in the manner mentioned, when every other method had failed. I have never yet known a cafe to occur where the pelvis was tolerably proportioned, in which I could not either obtain accefs to the feet to deliver by turning, or reduce the arm and bring down the head; and have, in several cafes, fuccefsfully turned where the pelvis was confiderably distorted.

It may be neceffary, however, to ftate the principles of this operation, that we may be aware how far to truft the unaffifted efforts of the constitution.

The longitudinal contraction of the uterus, is one of those blind and indifcriminate attempts which nature fometimes makes to free herself from a burden. When her powers are exhaufted, thefe efforts are diminished, and the uterus is relaxed. In thefe circumftances, then, if we can fix the arm, the body will of itself turn as on an axis; and the heavier part, or the breech, will come downward and be delivered: the arm is fixed by drawing down the fhoulder; but it will be obvious, that the natural falling down of the breech will immediately draw it back again; and it is in this way that the child does not ultimately come down double. This operation can be easily imitated on machinery, if the aperture is conical to fix that part which reprefents the arm; and it is în

this way clear, that the contradiction to the laws of motion is apparent only.

In the manner we have juft ftated, this mode of delivery may feem to be preferable; but various circumftances dimi nish its advantages. Dr. Denman has very properly limited. it to the delivery of a dead child, and we may add a wellproportioned pelvis: but, even there, we exhauft the powers of nature, without an adequate advantage; especially if we reflect, that, in this exhaufted ftate, an inconfiderable increase of the ufual discharges may prove fatal.'

In the Appendix, Dr. Hamilton takes notice of Dr. Ofburne. He had before corrected fome of the mistakes which he had inadvertently been guilty of, from misinformation; and now endeavours to defend his directions for fixing the crochet, and his recommendation of the Cæfarean section. The method which he mentioned was that, he fays, of Dr. Smellie and Dr. Young, while the very shape of the inftrument shows that it was originally intended to be fixed chiefly on the outside of the child's head. Our author obferves, that he has frequently recommended the bafis, for the place on which the inftrument fhould be fastened, though he still thinks his former directions fometimes proper, Indeed we lately witneffed a cafe where it was impoffible to fix it any where elfe. The Cæfarean fection, he says, was always, in his opinion, a last and defperate refource though delivery is fometimes practicable in a very narrow pelvis, yet the folidity of the child's head will not always permit it to pass in the circumftances mentioned by Dr. Ofburne. In that cafe, though defperate, it is the only measure, and he thinks it preferable to being a melancholy fpectator of death, without an effort to prevent it. In the work itself, Dr. Hamilton expreffes much less confidence in the authors formerly quoted, who were faid to have performed this operation. With refpect to the divifion of the fymphyfis, he agrees very nearly with Dr. Ofburne.

On the whole, we think this performance, though not free from trifling errors, a refpectable one; and its utility is increased by references, for the explanations, to the accurate and elegant plates of Dr. Hunter. These works will confequently reflect a mutual light on each other.

Practical Obfervations on the more obftinate and inveterate Venereal Complaints. By J. Swedia'r, M. D. 800. 2s. 6d. Johnson.

THE

HE uncommon candour and good fenfe difplayed in this work will strongly recommend it to every practitioner; and we think that there are few who will not derive fome inVOL. LVII. Jan. 1784. ftruction

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