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confirm it. We shall first, then, direct the inquirer's attention, as a general idea of salubrity, to a gravel foundation and the goodness of the earth, then to the growth of trees and herbage that he sees upon it, for these have all great influence on the air and on the constitution of man ;* and we shall in the same manner advise him to make his first conjecture by the general face of things, including even that of the buildings as well as the inhabitants, and to demonstrate and confirm the result of these inquiries afterwards.

With respect to the old buildings in the neighbourhood, if he perceives the slates of the roof and the stones of the walls sound, clear, and fresh on the surface, it is a proof that the air is pure and dry; on the other hand, if the roofs and walls be stained, tinged, or clogged with green, yellow, grey, and other coloured moss, and if lichens and herbage are growing upon them in abundance, we may look upon it as a proof that the air is damp and bad; and frequently here the masonry may be seen corroded with hollow, perforated, or indented reddish streaks, a further proof of unhealthiness.+ In general he will find the buildings that stand on elevated situations, and good free soils with gravel below and in a free pure air, assume the former character; while those which are situated in low lands on damp soils with clay substrata, and the house choked up around with trees and thick underwood, are of the latter character.

If trees, by their regular growth and freeness from moss, with a thriving aspect, declare the goodness of the ground, let him next observe the cattle in the adjoining fields, to ascertain what is the condition of their health, on which the air as well as the vegetation and water materially act. Provided the pasture and water be good, these animals cannot fail to thrive; but where there is a fault in either, the cattle will be sure to show it by their appearance. If they be sleek, brisk, and strong, it shows that the air is good and the water pure and wholesome; if they be feeble, ragged, poor, and dull in their movements, the fault is commonly in one of these two particulars, and most probably in the latter.

From the brute creatures let us turn to the inhabitants of the place, for in them, particularly in their faces and conditions, we shall read the most certain accounts of the general healthiness or unhealthiness of the situation. A good body, buoyant spirits, fresh complexion, and strength to labour, are marks of health that can neither be disputed nor mistaken; and such healthy and goodconstitutioned people are sure to be found in those distant towns near commons and heaths,§ where the air is bracing, and in those milder and pretty villages through which a pure stream of water is constantly gliding: it is here the inhabitants are sure to be free from those headaches

* The elements of which vegetables are chiefly composed are oxygen, carbon, and hydrogen, which they throw out; and with these and the assistance of light and heat nature forms all the different varieties of vegetation with which we are surrounded: the lily, the violet, the tulip, the rose, with all their various tints and perfumes, are only more delicate arrangements of the same materials which form the massy oak and stately fir.-(Elements of Chemistry.)

+ These perforations on the face of the stones are produced by a nitrous acid, which combines with calcareous earth, and forms what is termed earthy soft patre. Of the former, where there is a putrid fermentation of animal and vegetable matter in hot countries, it is known to effervesce from the earth in large quantities, so as to destroy the very masonry of the houses. (Brenton's Naval Hist., vol. iii. p. 139.)

The elm, it may be observed, is always found growing on good ground, the oak on the bad; but the elm must have a moist soil, while the oak requires the dry.-(B.)

§ Norden, who published, in 1595, an Historical and Chronological Description of Middlesex, says of Highgate, which is situated near a common, " Upon this hill is most pleasant dwelling, yet not so pleasant as healthful; for the expert inhabitants there report that divers that have been visited with sickness not available by physicke, have in a short time repaired their health by that sweet salutary air." Norwood, Sydenham, and Beulah on the Surrey side of London may surely now vie with Highgate.-(B.)

|| I shall here give a poetical description of such a sequestered spot, which I have lately visited, and where the enemies to the picturesque have not yet lifted the hand of art to destroy the beauties of nature. Here is attraction both of wood

which prevail in towns where they have not the advantage of this running brook through its streets.*

There is something in the air of a healthful situation that is, as it were, the object both of taste and smell; we perceive it as we inhale it, particularly in the morning; we feel its lightness by its buoyancy on our spirits, and are scarcely ever mistaken in judging of it by that means; but it is only in mid-heights or elevated places that we enjoy the effect of its purity. In the same manner that we perceive this the moment we breathe it, so we are struck at once by that appearance of robust health we see in the faces of the inhabitants in healthy spots; nor are we more mistaken in one than in the other. Our own species are the most helpless and tender from youth to age of all the animal creation, and feel the bad effects of air sooner than the others; but we are endued with reason, which is denied to the brute. The cattle will show the natural effects in a bad place, as has already been observed.‡

Men show the lesser defects of the place in their countenances, and are affected by every fault to which the spot may be subject, whether by that of impure air or water. As we are liable to more disorders than other creatures, and these, too, more easily fall upon us, it is a reason why we should endeavour to guard or avoid what occasions them. When we have our choice of the many counties in England in which to fix our residence, it would be an unpardonable error to seat ourselves where any great inconveniences prevail, much more where the means of preserving health are absent, which is the greatest of all.§ We should therefore well consider the healthiness of the place by all the signs which have been enumerated, as well as whether it is subject to frequent

and water; and pretty, neat, unassuming little villas are seen peering among the trees which surround them, each situated in a garden, and rising over each other, like the seats of an amphitheatre, in gentle, sloping terraces. Now,

"This village has a pleasant look,

A happy look as e'er was seen.
Right through the valley flows a brook,
Which winds in many a flowery nook,
And freshens all the green.

On either side, so clean and white,

A row of cottages you see,

And jessamines are clustered o'er
The humble trellis of each door,

Then left to clamber free,

And shake their blossoms far and wide
O'er all the whitewashed cottage side."
(Budleigh-Salterton, Devonshire.)

Abundance of water constantly runs through the city of Salisbury.

+ Damp, cold air may be observed by breath from the nostrils, which cannot be perceived in a dry and warm air. This is common in the winter season; but heavy air is known by its weight on our eyelids.-(B.)

It must be borne in mind that their disorders are at times, nevertheless, produced by being in the open fields, where they are exposed to storms, rain, snow, and sleet, and by lying on the ground in very wet seasons.--(B.)

§ If, say the Persians, the soil of Ispahan, the fresh air of Herat, and the waters of Kharassan were united in one spot, the inhabitants of it would never die. (Persian Proverb.) Ecbatana, now Hamadan, was the summer capital of the sovereigns of the Persian empire from the time of Cyrus, while the winter metropolis was Susa. The intense heat of summer in the plain of the Tigris, in which Susa was situated, and the very mild character of the winter, rendered a residence in it as inconvenient in the one season as desirable in the other; while, on the other hand, the elevated site of Ecbatana gave so much mildness to its summer heat and severity to its winter cold, that it enjoyed a mild climate when that of Susa was most oppressive, and a severe climate when that of Susa was mild. This periodical change of residence by the Persian kings attracted the attention of most heathen writers, one of whom, Ælian, compared them to cranes, that change their places with the seasons. (The same was observed of Lucullus from his choice of villas.)

The description of this summer city, as given by Herodotus, is so curious that we cannot omit it. He says it was built by order of Deioces, who first established the Median monarchy: here he caused his subjects to build a city, which eclipsed all others then existing in Media. It stood on a circular hill, which was surrounded by seven walls, rising within each other in such a manner that each wall rose above the next without it by the height of its battlements. The royal palace was within the last wall. The most extended of the walls at the base of the hill was nearly equal to the circumference of Athens. The battlements of this outer wall were white those of the second, black; of the third, purple; of the C C

changes of weather arising from local attractions, before we determine on making it our place of abode; for remember, though we may now be in good health,* yet we are not sure how long we may be allowed to enjoy that benefit, and that

"Though the blessing 's lost with ease,

'T is not recovered when we please."-DR. COTTON.

That climate has a great effect on the spirits we have instances at Naples; for in that capital may be observed a great activity of mind among the inhabitants, and a wonderful aptitude, fostered by the serenity of the atmosphere: the people there excel in every branch of science and composition ; so beautiful is its neighbourhood, so delicate its climate. Before it spreads the sea, with its bays, promontories, and islands; behind it rise mountains and rocks in every fantastic form, and always clothed in verdure; on each side swelling hills and hillocks, covered with groves, and gardens, and orchards, blooming with fruit and flowers. Every morning a gale springing from the sea brings vigour and coolness with it, and tempers the greatest heats of summer with its freshness. Every evening a breeze from the hills, and sweeping all the perfumes of the country, fills the nightly atmosphere with fragrance. It is no wonder that the Romans covered its coasts with their villas, and that so many poets should have made the delicious Parthenope their theme and their retreat.+ The general occasion of some places being unhealthy we shall treat of in the next Dissertation, when regarding air; and occasionally after that, on the water and the soil, and other local circumstances; but here the attention is to be drawn to the plain and most certain methods of satisfying ourselves, or judging rightly by self-evident rules. There is this, namely, to be observed respecting the healthiness of a place, that one man may have, by a peculiar circumstance, an advantage over another in fixing upon a spot particularly healthy; but it is better with this advantage when all the grounds which environ the site are healthy, and the house good also; for where the adjacent grounds contain stagnant water and thick brushwood obstructing the air, this peculiar spot is not of itself a sufficient benefit, for the good air may be affected by the bad, therefore the circumjacent grounds should be equally considered and examined. The complexion and bodily strength of the inhabitants, as we have before remarked, will, however, show the general constitution of the country in that particular spot, and such select situations may always be obtained. Finally, that person would be but very weak of intellect who should fix his residence where every person he met was shivering with an ague, had pallid cheeks, or a hectic cough; while, on the contrary, he might be reasonably tempted to the spot where he saw nothing but health in the countenances of the people, scarcely the trace of a recent grave in the parish churchyard, and read of eighties and nineties on their tombstones. Now, above all, I should recommend a place where there was but one medical practitioner; and he, for want of business, should be as lean as Shakspeare's apothecary in Romeo and Juliet.+

fourth, blue; of the fifth, orange: the battlements of each wall being thus distinguished by a different colour. The battlements of the last two (uppermost and innermost walls) were plated, one with silver and the other with gold. Such a city must, on a distant view, have made a very striking appearance when illumined by a midday sun.—(H.)

* "O blessed Health! thou art above all gold and treasure. 'Tis thou who enlargest the soul and openest all its powers to receive instruction and to relish virtue. He that has thee, has little more to wish for, and he that is so wretched as to want thee, wants everything with thee."-STERNE.

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DISSERTATION III.

ON THE GENERAL PROPERTIES OF AIR.

"This guest of summer,

The temple-haunting martlet, does approve,
By his loved mansionry, that the heaven's breath
Smells wooingly here: no jutty frieze, buttress,
Nor coigne of 'vantage, but this bird hath made

His pendent bed, and procreant cradle. Where they

Most breed and haunt, I have observed the air is delicate."
SHAKSPEARE'S Macbeth.

We should consider the air amongst the first and most important advantages in a situation, because it is for the benefit of this that we frequently retire into the country; and we live so immediately by it that the very period of our existence will be greatly determined by its qualities:* our health will of necessity depend upon it, and upon that the enjoyment of every other blessing. Our consideration of air is not here for the sick, for according to the different nature of disorders various temperatures of air are required; sharpness being the principal recommendation to some, while softness is more congenial to others. These are considerations alone which regard the choice of an occasional spot for the recovery of health; but our inquiry is here respecting such a quality of air as will preserve health, one that is buoyant, salubrious, and most universally agreeable.+

More essential is it to choose a good air for our place of residence, because that which is faulty, it is not always in our power to correct, although, under some local circumstances, we may mitigate it. If, for instance, the place be choked up with trees and thick underwood, obstructing the free circulation of air, or if there be growing around the spot baneful weeds, such as deadly nightshade, hemlock, henbane, &c., "within whose rind poison lurks, holding an enmity with the blood of man ;"

* Light and heat are essential to life as well as air. The sun produces both; and where that agent has not access, as in a dark room, and plants have been placed therein, they have been soon observed to die. Hence the reason of more of the human race dying by night than by day.-(Rogers' Astronomical Lectures.)

+ To comprehend the nature of air and the atmosphere in which we live, which is indeed of itself one of the principal agents of our existence, it is necessary to state, that the atmosphere is supposed to ascend upwards from the surface of our earth a little more than five miles: in the winter season, on account of its heaviness, it is of course less; above which is ether. That it is composed of two different fluids, which have been described by natural philosophers under the appellation of azotic and oxygen gas, or phlogisticated and vital air. (The air we breathe is composed of two gases, oxygen and nitrogen, in the proportion of twenty-two of the former to seventy-eight of the latter. If we take the same gases and reverse the proportions, combining seventy-five of oxygen with twenty-five of nitrogen, we produce that powerful corrosive agent nitrous acid or aquafortis.) In one hundred parts of atmospheric air there are contained about seventy-two parts of azotic gas to twenty-seven of oxygen, besides one part of carbonic acid gas or fixed air, which is generally found united with them; or, to speak in round numbers we may say, that the air of our atmosphere we breathe contains rather better than one-fourth of pure or respirable air, and that a remaining three-fourths are unfit for respiration and equally unfit for combustion, since the same fluid which supports flame is equally found to contribute to the support of animal life.-(Priestley on Air.)

Azotic gas being specifically lighter than oxygen, it might naturally be supposed that, since they only exist in the atmosphere in a mixed state, and not in a state of chemical combination, a spontaneous separation would take place, and the azotic would occupy the higher regions in the atmosphere; whereas it is found by experiments with the eudiometer, that the upper regions of the air actually contain a greater proportion of oxygen than those nearest the surface of the earth.— (Brisson.)

Extraordinary as the mixture of fluids in the atmosphere may appear, it is essential to our earth, and even our existence, and demonstrates no less the wisdom than the goodness of Divine Providence. This pure vital air, so wholesome, so necessary in a moderate quality, like spirituous liquors or salutary medicines, must be dispensed with precaution, as it would be fatal in the excess. If we were indeed to breathe pure oxygen air without any mixture of alloy, we should infallibly perish by the unnatural and fatal accumulation of heat in our bodies. If, again, the whole atmosphere was composed only of vital air, combustion would not proceed in that gradual and moderate manner, which is necessary to the purposes of life and of society; even iron and all the metals themselves would then blaze with a rapidity which would carry destruction through the whole expanse of nature.-(B.)

or a place which is surrounded with quagmires and foul waters, the habitations of newts and tadpoles, which will also render the air unwholesome;-if this be the sole cause, and it belongs to the same proprietor, the air may be amended by cutting down the former and filling up the latter places; but if this is not entirely the occasion of its badness, then it cannot be obviated but in a certain degree, and that, perhaps, attended with a great expense. When the effect arises from natural causes, and the air is in any great degree polluted, no price will purchase the perfect cure; it is altogether beyond the power of human capability.

As we always live surrounded with air, and perceive by daily experience that it can and does enter, with all its qualities, into our constitution, and that when bad or impure it vitiates the whole fluid of the human blood, it is necessary to examine the air on the spot, by some philosophical experiments, before we begin to build. In the most general instances of the air being vitiated by circumstances or by accidents of nature, we find that it occasions very alarming and desperate diseases. Where the air is always damp, ague, rheumatism, fluxes, cholic, and consumption are frequent; and wherever it is impregnated with the steam of mineral matter or from gas-works, palsies and other of the greater and lesser nervous disorders are certain to be the consequences. It is in the same manner that the air, in whatever way it is faulty, will, according to the nature of that taint, affect the constitution. When we have once sat down in it, we cannot remove without giving up all that we have been doing in building and planting. Many instances might here be adduced, if necessary, of such inconsiderate undertakings, to show how absolute is the folly of imagining that art and ingenious contrivances can always correct it. That the felling of thick woods and draining meadows and marshes render a country more healthful is readily admitted. But marshes even at a distance, and though they may belong to a neighbouring proprietor, yet we know that water raised in vapours is rendered portable even upon the wings of the lightest breeze, and is wafted with greater facility than air itself into the higher and mountainous regions of the land.

As many disorders are evidently the constant and certain effects of bal air, health, comfort, and cheerfulness naturally follow from breathing that which is fine and pure. To be good, in general

* All the vegetable tribe emit gas, and so do all poisonous liquids and substances: thus stagnant water diffuses a quantity of mephitic air or vapours through the surrounding atmosphere, and some of these consume the pure or vital air. Even the vapour of pure water in considerable quantities is pernicious to animal life. Of this the Arabs were well aware, who being intent on injuring the Turks at Bassora, broke down the banks of the ver near the city, so as to permit it to overflow a great tract of land, a violent fever being generally the consequence of the putrid mass left behind after the water had evaporated.-(Cave on Air, p. 457.)

By the evaporation from our earth, the air contains a large quantity of water which even in the driest state of the weather is very considerable. We may be said to walk in an ocean, though this water does not ordinarily become the object of our senses: we cannot see it, nor, whilst it continues dissolved in the air, do we feel that it wets us; but it is still water though it be neither tangible nor visible; just as sugar when dissolved in water is still sugar, though we can neither see nor feel it. We may conclude that the Almighty, when he separated the chaotic mass into air and water, did not render them two oceans, so wholly heterogeneous from each other as that they should be incapable of contracting any union; they have, on the contrary, such a disposition to unite as seems to indicate their having had a common origin; and were it not for the intervention of heat they would probably unite, and again compose a common mass. The water on the surface of the earth is constantly replete with air, and the atmosphere is replete with water. The numerous tribes of aquatic animals which inhabit the ocean would perish if it contained no air, and it is not an improbable conjecture that the animals which exist in the air would perish if it contained no water. The air moreover by being absorbed into the water, and afterwards separated from it by the action of the sun, is rendered abundantly more fit for animal respiration than common air; and this purified air (the quantity of which, considering the great extent of the surface of the earth, which is, says Lehman, two-thirds covered with water, must be considerable) cannot be but one great means of restoring to the whole mass of air these salubrious qualities of which it is daily deprived by the respiration of animals, the putrefaction of bodies, the combustion of fuel, and other causes.-(Watson's Chemical Essays.)

+ Cultivation, without doubt, while it opens the thick recesses of woods, and carries away stagnant waters, not only purifies but warms the atmosphere, and from thence extends its beneficial influence to the adjacent countries: this we have observed in America, where the yellow fever, which prevailed to an alarming degree on the first colonization of that country, has now greatly subsided.-(My Note Book.)

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