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so very small, that doubts will probably be entertained whether they will justify his deductions from them.
It will be doubced, for instance, whether any decisive conclusion may be drawn from observing the temperatures of a mixture of two fluids, differing in specific gravity fo very confiderably as water, and common, or dephlogisticated, air; though he gives to the latter -100 degrees of heat more than to the former. Thus a pint of ai. mospherical air, contained in a bladder, and raised to the temperature of 163 degrees, is in mersed in a piot of water at 63 degrees; that is, in a quantity of fluid containing above 800 times more mat. ter than jifelf. Had the atmospherical air contained the same abfolute heat with water, the Author calculates that it would have communicated to the water nearly the one-fixteenth part of a degree of heat : . but it communicated to it one intire degree of heat,'--He concludes therefore, that almospherical air muit contain at least 16 times as much absolute heat as water. From similar experiments made with depblogisticated air, he calculares that it communicated three degrees of heat, &c.
Even the greatest of these differences is so small, that there is reason to suspect, potwithstanding all the Author's accuracy and care, that they may pollibly have proceeded from caufes different from those here afligned. With respect to such differences, there is some reason to apprehend that they may proceed either from caules wholly unknown and unsuspected ; or from others, the effects of which are too difficult, or minute, to be accurately ascertained.
Notwithstanding this remark, which cannot well have escaped the sagacity of the Author himself; we hope he will prolecule his ingenious inquiries, for which he appears to be so well qualified. There are undoubtedly many phenomena in nature, well explained by this hypothetis ; which, as well as the Author's various and well imagined experiments, deserve the attentive consideration of philosophers.
Art. XIV. A Plan of the navigable Canals made, and now making, in
England. Lowndes. THIS Plan (as we learn, by a new edition of The History
1 of Inland Navigations, published with it) is done from actual surveys, made and drawn by Mr. Hugh Henfall, engineer, and successor to Mr. Brindley; it cannot, therefore, fail of proving very acceptable to the public. l: gives a clear and distinct view o? one of the most extentive and important general improvements that this nation ever experienced; the confequences of which muit be as durable as the existence of the le valuable works. When a manufacturing and commercial nation, through excess of riches, luxury, and taxation, can no Jonger bring its productions 10 market at a moderate price; and when other countries, by reason of cheapness, begin to underfell it, the decay of such rich nation would then be infallible, and extremely rapid, if this natural cause of declenfion were not retarded by the exertions of genius, in the ap
plication plication of mechanical powers to the business of manufactures ; -by which means alone the destructive effects of abundant riches, and high taxes, can be suspended, and an industrious nation, in such circumstances, be preserved from ruin. The manufactures of Birmingham, Manchester, Sheffield, &c. have long existed upon these principles; and the manufacturers have been enabled, by the ingenuity and variety of their mechanical inventions, to support a rival trade againft all Europe, and supply countries (where human labour is much cheaper than in this with their commodities.
But among all these improvements, there are none so fundamental, so extensive, and so powerful, as that amazing system of water roads, exhibited in the plan now before us; and which realise all the advantages to this nation, long since foretold in various publications on this subject. All the central parts of the kingdom, and almost all the manufactures, now enjoy, or soon will enjoy, the unspeakable advantage of a reduction of more than two-thirds of the price of carrying all heavy articles; many thousands of devouring horses will be rendered unnecessary;-and if our public measures were conducted with as much wisdom and spirit as the affairs of individuals, and those who take upon them to protect and lead us, would please either to act their part well, or do nothing, there is no doubt but this nation might still go on improving; and that its natural and artificial advantages might support it in wealth, honour, and power, for many ages. - But before we take leave of the Plan under consideration, we cannot help observing one capital defect in the execution of this great fyltem of canals, which, we are well informed, might easily have been prevented when the act for the Stafford. thire navigation, or the Great Trunk, as Mr. Brindley called it, was obtained. The Duke of Bridgewater's canal, the Staffordshire canal, and consequently, all those that now do, or ever may fall into them, by a narrow and selfish policy, are made to terminate in the Tide-way of the river Mersey; when they ought to have been carried over that river by a grand aqueduct into Lancashire, and to the port of Liverpool ; where they might have been joined by other canals and branches from different parts of Lancashire and Yorkshire; and the whole system of canals might reciprocally have communicated with each other, without going into a ride's way, or making it necessary to trans-fbip the goods. This noble plan was proposed at the time, by a zealous and active friend to these undertakings; a meeting was had upon it at Runcorn, the place where the navigation Thould have crossed the river ; all the parties declared, it would be the best plan for the public intereft ; Mr. Brindley approved of it, and declared it so be practicable, both . Cc 2
at this meeting and before the House of Commons ;- where he was very particularly examined upon this point; and yet other views and interests prevailed, and this great work was left to be completed by posterity, for whose fake we leave this memo. randum of a transaction in which they may be interested; at the same time, referring them for farther particulars to the Journals of the House of Commons.
There is another obvious defeat in this system of canals, for want of an extension of the Staffordshire canal from some part near Derby to Chesterfield, which certainly will be removed when the proprietors of the Staffordshire and Chesterfield Canals, and the land-owners between Derby and Chesterfield come to understand their true interests; and to consider the benefit that must arise to them and the public from the proposed communication ; by which means, the goods from Staffordshire and the neighbouring counties, would be delivered above fifty miles lower upon the Trent than at present, and the county of Derby receive great advantages in the conveyance of its natural productions, and in many new manufactures and establishments, which these in:provements never fail to produce.
This new edition of the History of Inland Navigations corttains several useful tables of distances, rates of freight, &C. and is, on the whole, a valuable collection of papers relative to the canals that have been projected, and executed, in this country. The last letter in this compilation takes notice of another great mechanical improvement, for which this nation is indebted to the philofophic fpirit of the age, and to the abilities of those ingenious philosophers and artists Messrs. Wat and Boulton, whose skill and activity we hope will be amply rewarded by their country * The writer, after speaking of the lime-kilns, near the Bridgewater Navigation, adds— Nor can I pass filently over the capital and new erected Salt-works, built upon the banks of the navigable canal at Thurlwood, in CheThire, the property of Messrs. Salmon and Purlington. In an adjoining valley, they have fixed a fire-engine, constructed by Meff. Watt and Boulton, which in the waste of three hundred weight of coals (value nine-pence) does in twelve hours throw up, to the height of a hundred yards, not less than twenty-four thousand gallons of brine; which is received in a very large re. servoir, and from thence conveyed to the salt-pans, where the falt is extracted and loaded into barges, in which it is carried into Staffordshire, Derbyshire, and the neighbouring counties.'
We have cast up the lengths of the several canals included in the plan, and we find, that they amount to 556 miles, and
• See an account of Mr. Watt's great improvements on the invention of the Steam Engine, Rev. vol. lvi. p. 40.
a few chains; and we apprehend, that they cannot have cost less than one million fterling : perhaps considerably more.
We have observed a mistake or two in this plan; one of which ought, particularly, to be corrected, viz. Bursem, in Staffordshire, famous for its Earthenware Manufacture, is placed on the wrong side of the canal.
For NOVEMBER, 1779.
POLITICA L. Art. 15. A Letter from Lieutenant General Burgoyne to his Confi.
tuents, on bis late Resignation; with the Correspondences between the Secretaries of War and him, relative to his Return to America, 8vo. Is. Almon. 1779.
ENERAL Burgoyne here (to use the words of one of his U ANSWERERS) recapitulates his fervices, his endeavours, his ex. pectations, and his disappointments; and he addresies his parliamentary conftituents, the freemen of Preston, in such terms, as he may apprehend to be belt suited to conciliate their regards, and secure their interests, at the next eleclion. His style is such as may be expected from a man whose feelings are unusually irritated, and his resentment warm. He considers the ministry as the plotters of his destruction; and he even goes so far as to declare, that 'the ruin of officers forms almost the whole of their military system'- But, furely, this is rather the language of despair and faction, than of a sober and TRULY PATRIOTIC opposition to the measures of an incompetent or wicked administration ! Art. 16. A Letter to General Burgoyne, on his Letter to his Con
ftituents. 8vo, 15. Becket. Contains mapy just ítrictures on the General's letter, but is written with too much acrimony. Instead of the liberal manner of a gentleman, the Writer attacks Mr. Burgoyne with the ferocity of one of his own savages, reeking and hot from the murder of poor Mifs Macray. Art. 17. A Reply to Lieutenant General Burgoyne's Letter to his
Constituents. 8vo. 13. Wilkie. This answerer merits commendation for the decent and candid ftrain in which he writes. He does not, like the General's antagonit above mentioned, affail with a blunced tomahawk. His weapon's are of a finer polish, and keener edge. He does no: hew and chop like a butcher. He cuts up like a kilful surgeon ; and diffects his subject with the dexterity of an abie anatomist. -The following half of a parallel between the case of Regulus, the celebrated Roman General and captive, and that of General Burgoyne, may be ex. tracted for the farther satisfaction of our readers :
"Lieutenant GenerAL BURGOYNE was entrusted with the command of an army dettined to perform a material service to the state. His conduct was marked by zeal for the expedition upon which he was employed; and wherever he met the enemy he combated with valour. Victory for a time seemed to contend under his
standard; but at length she deserted him, and he was exposed to the malice of Fortune. The enemy collected a force greatly exceeding his in numbers; and he was compelled to yield to their superiority. While a prisoner in the possession of the enemy, he obtained permife son to return to his own country ; but he continued engaged to redeliver himself up to the enemy upon due notice being given to him. Upon his arrival, he found himself precluded from the presence of his Sovereign, upon prerence that an Inquiry was to take place into his conduct, and that it was unfit he mould appear at Court till the event of that Inquiry was knowo. He demanded a Court Martial; but this was denied him, upon a representation from the heads of his profession, that it could not be held upon him while he continued a prisoner. He complained loudly of both these measures, and joined himself to a pariy which acted upon a plan of general opposition to the Ministers of their Sovereign. Lieutenant General Burgoyne was a member of the Senate. There he attempted to take the lead upon many important occasions. It was observable, that his chief complaints were of the personal ill-treatment which he had received ; and that he seemed to feel his own wrong more sensibiy than the loss of his country. He received an official order signifying to him, that it was the pleasure of his Sovereign that he should return to America and join his captive a: my, who were suffering under cruely and disgrace. He thought fit to represent what he supposed the leverity of chis order. Again he was commanded; again he remonftrated; and at length finding the matter firmly inlifted upon, he resigned all his civil and military employments, reserving only his rank in the service. He gave an account of his conduct to the public in a letter which he addressed to his Constituents, and inveighed with bitter acri, mony against the Minifters of his royal malter. This letter was received with a difference of cpinior.. Some chough it a patheric representation of unnecessary severity; some considered it as a juftification of his conduct; and there were not wanting some who fronounced it A LIBEL UPON THE King's GOVERNMENT,'
MEDICA L. Art. 18. Cafes ard Remarks in Surgery; to which is subjoined
an Appendix, containing the Meched of curing the Bronchocele jn. Coren:ry. By B. Wilmer, Surgeon. Svo. 5 s. 'Boards, Longman. 1779.
From the miscellaneous contents of this volume, we shall releet Such articles for the information of our readers, as appear moit likely to be new and important.
The Author begins wish fome observations on ftrangulated herniæ. The chief purpose of these is, to congirm the doctrine maintained by fome late writers, of the superior efficacy of cold and altringent applications, above warm and relaxing ones, in procuring the reduc. tion of the hernial contents. Some cases are related frongly in favour of this opinion. The Author met with equal success in the treatment of the hernia humoralis after the same method.
In the hisory of a fractured ikoll, the Author takes occafion to plead against the necessity of removing a circular piece of scalp in all fractures ; a practice cruel in the execution, and which greatly retards the subsequent cure. A fingulat case follows, of a large