after a morning prayer, in which their faces were | fruition, is agreeable to us. directed towards the rising sun, was broken up.

having its own mode of sensibility. Still there is, as already intimated, a close, and one may call it, instinctive connexion of function between the two; and hence, among animals generally, the sense of taste, as far as concerns the ingestion of fluid, may be safely relied on as interpreter of what will be agreeable and salutary to the stomach. The same remark might be made of our own species, if we were attentive to preserve the early purity, and, as it were, instinctive discrimination of taste, and not force it to recognise as customary stimulants, various condiments, spices, and intoxicating drinks.

Hence it is, that we meet with so many arguments in the shape of aphorism, verse, rhetoric, and wit, in favor of intoxiTHERMOMETER. An instrument for meas- cating liquors. Not that these drinks are at first uring the temperature of the air, as respects heat so palatable, but, with a little practice, the result and cold, founded on the principle that the expan- of imitation, they stimulate the gustatory sense in a sions of matter are proportional to the augmenta- manner which becomes finally to be considered as tions of the temperature. The invention of the necessary to one's comfort. It is thus that we are thermometer has been ascribed to different authors, taxed for indulgence in every uncalled for and bad to Cornelius Drebbet of Alcmaar by his country-habit. Be it said, also, that the sense of tastemen Boerhaave and Muschinbroeck; to Father though in close alliance with the digestive sense in Paul, by his biographer Fulgenzio; to Galileo by the stomach, is not always a faithful sentinel to this Vincenzio Viviani; but Sauctorino assumes the latter. However desirable it may be to insure geninvention to himself, and his claim is fully admit-eral harmony, we are not to look for identity of ted by Malpighi and Borelli. The first form of sensation between the two, since the tongue and this invention was the air thermometer, consisting the stomach are supplied by different nerves, each of a glass tube connected at one end with a large glass ball, and at the other end immersed in an open vessel or terminating in a ball with a narrow bottom. The vessel was filled with a colored liquor that would not easily freeze, as aquafortis tinged with a solution of vitriol or copperas. The ball at the top being then moderately warmed, the air contained in it was in part expelled, and then the liquor pressed by the external air entered at the lower ball and rose to a certain height in the tube, according to the temperature. The air being found not so fit for measuring with accuracy the variations of heat and cold according to this form of the thermometer, which was first adopted, alco- Thirst is a sensation, amounting, at times, to a hol, or spirit of wine, was used by the Florentine real irritation, or a want, felt in the throat and academy, enclosed in a very fine cylindrical glass stomach. It is brought on by whatever stimulates tube, having a hollow ball at one end, and hermet- these parts in such a way as to exalt sensation and ically sealed at the other. To the tube is applied a diminish the customary discharge of fluids from scale, divided from the middle into one hundred their surfaces-hence, thirst is excited by condiparts, upwards and downwards. As spirit of wine ments and vinous and spirituous drinks. This is capable of a very considerable degree of rarefac- want is also greater by whatever stimulates the tion and condensation by heat and cold, when the blood vessels and nerves of other parts, with which heat of the atmosphere increases the spirit dilates, the stomach sympathizes; and on this account it is and consequently rises in the tube; and when the very urgent, in consequence of exposure to the heat decreases the spirit descends. As inconve- sun's rays, and in a heated atmosphere, which last niences were found to attend each of these ther-stimulates both the skin and the lungs: burns will mometers, as also that of M. Reaumur, which was cause raging thirst: fits of passion, by their excitconstructed in a similar manner, Mr. Fahrenheit ing powerfully the nervous system, have the same first employed mercury for this purpose, which effect. has since been universally adopted. The method of constructing this thermometer, is as follows; a small ball is blown at the end of a glass tube, of an uniform width throughout. The ball and part of the tube are then to be filled with quicksilver which has been previously boiled to expel the air, the open end of the tube then being hermetically sealed, a scale is constructed by taking the two fixed points, namely, 320 for the freezing point and 2120 for the boiling point, and dividing the intermediate space into equal parts, or 180o.

THIRST. Distinct from the first and most important purposes for which we take drink, viz. for allaying thirst, and for diluting the solid food taken into the stomach, there is another motive which has great influence over us all; and that is, to gratify the taste, and to tickle the palate. Present pleasure makes us too often oblivious of the future pain and evils which may follow its indulgence; and we are never such ingenious sophists, as when we are finding reasons in favor of a thing, or practice, which, at the moment of temptation, or actual

Thirst, unappeased, excites in its turn the whole animal economy-the senses, which become morbidly acute; the brain, which is rendered irritable and prone to manifestations of impatience and anger; the circulation accelerated and febrile, and the skin hot and parched.

Thirst thus brought on, and augmented by external heating and irritating matters, and by irritation in various parts of the animal economy; and when present, giving rise to increased heat and irritation of the functions generally, can of course, be mitigated and removed but by one class of agents. These are of a cooling, soothing and sedative nature. Cool air applied to the skin and inhaled into the lungs, or cold water applied to the extremities will sometimes answer. A depressing emotion, as of sudden fear, will, by its prompt sedative action on the nervous system, produce the same result. But that which above all other means is best calculated to soothe the heated and irritated surfaces of the throat and stomach, and thus remove all the troublesome secondary symptoms, is to drink simple water, or the blander watery fluids. The in

stinctive want of such fluids for drink, is strongly | and throat, and a nearly analogous state of the up pronounced from the lowest animal up to man. per orifice of the stomach, in which thirst is more They soothe the irritated sentient surfaces affected particularly felt. In such cases, a saccharine or in thirst; they furnish matter for the absorbents of mucilaginous fluid, such as the juice of the sugar these surfaces to carry into the circulation, and cane, or molasses with water, gum arabic with thus to preserve the requisite proportion of water water-are the best drink, since they sheathe, as it in the blood. were, the parched surfaces, and by being less readWhile simple aqueous moisture is the chief as-ily evaporated, preserve them longer moist. suager of thirst, and that without which the want would soon become a raging inflammation and fever, leading to death, yet does temperature also exert a modifying influence. Coldness of the fluid contributes more effectually to allay the nervous irritation in extreme thirst; but, though agreeable at the moment, it is not essentially necessary, and is often hazardous, after the individual has been enfeebled by long and excessive exercise and labor. The safer plan in such a case, is to apply the cold fluid iced or spring water to the hands and face, and use for drink that which is of the temperature of the river or flowing stream. Even in hot weather, water of the temperature which it assumes when exposed to the air, is the best quencher of thirst, though not the most grateful to the taste. Very cold water taken into the stomach, in some cases deadens the senses and produces spasm, and even death. In the most favorable condition of the animal econo-ed in it, as we find by putting in a lump of sugar my it is apt, especially in vigorous habits, to give rise to great reaction-increased flow of blood and sensibility of the parts, and of course a fresh call for drink.

But in addition to these means of relieving thirst by moistening the mouth and throat, allaying the heat of these parts and of the stomach, and furnishing fluid for the absorbents to take up and carry into the circulation, all of which are best done by simple cool water; there are certain organs instrumental in the same end, and also in preventing us from feeling thirsty. These are the salivary glands, from which, by appropriate tubes, pass into the mouth a bland fluid calculated to lubricate continually the mouth and throat, and to be mixed with our solid food during the act of mastication. The very act of chewing will cause saliva to flow into the mouth-no matter how simple, or divested of all taste or chemical properties may be the body chewed; a piece of chip, or of tow, will have the effect-so also will a substance allowed to remain in the mouth and slowly dissolv

candy or of gum arabic. There are other articies which increase the flow of saliva by stimulating the salivary glands, such are acids, salts, condiments, and certain bitter and narcotic vegetable substances.

It is essentially necessary for comfort and health, were it only in obviating and preventing troublesome thirst, that saliva should always flow into the mouth and preserve the requisite moisture in it and the throat, and indeed in the stomach itself, supply of saliva is the consequence of excessive action of the salivary glands, as from habitual chewing or smoking of spices, tobacco, opium, and such substances, or from the protracted excitement of high seasoned food, various wines and cordials, At times, the discharge of saliva is obstructed when the system generally has been over-excited by intense passion, or otherwise in a heated and febrile state.

The lover of spirituous and fermented liquors, persuades himself that they are excellent quenchers of thirst and mitigators of heat; because he experiences relief from these sensations after he drinks them of an icy coldness. The benefit here was from the adventitious property of the liquor, viz. its coldness; but so soon as this has disappear-into which it constantly passes. Usually a deficient ed, then follows the stimulation and excitement from the alcoholic portion-the thirst is renewed, and if appeased in the same way, soon returns with increased urgency; and finally, the sipper of such liquors is at length brought into the fever of drunkenness, and is greatly surprised to find that his cold spirit and water, or cold wine, or beer, should heat him so excessively. The only element in most of these liquors, by which they at all palliate thirst, distinct from the effect of their artificial coldness, is water.

A very grateful addition to simple water, when used as a drink to quench excessive or feverish thirst, is vegetable acid, and especially the citric, that is furnished so largely in lemon juice; and also acetic acid or vinegar, and pyro-ligneous acid.

Some of the lighter wines and cider are at first refreshing from the acid they contain; but their effects in this way are more than counterbalanced by their alcoholic element, and their proneness to excite fermentation in the stomach, accompanied by sensation of heat and renewal of thirst. Experience teaches us, that acidity and heartburn are more readily produced by these liquors than by the simple or pure acid diluted with water.

Where the thirst is urgent and continued, that is of a feverish nature, it is not sufficient to swallow large quantities of fluid; the troublesome sensation is soon renewed by the prompt drying of the mouth

We learn from these facts, that in the absence of an abundant supply of fluid, a simple substance in the mouth, such as crystallized sugar or gum arabic, will greatly obtund the sensation of thirst, by moderately inviting saliva into the mouth, and keeping it moist; while, on the other hand, more acrid and irritating substances, whether solid or liquid, though for a short time, by stimulating the salivary glands, they cause an increased flow of saliva, yet they soon diminish and dry up, as it were, the supply, and in place of obviating, they increase thirst.

We have seen, also, that whatever stimulates the stomach and system generally, will give rise to an increase of thirst. Hence, to moderate and remove it, not only are bland drinks, chiefly simple water, useful, but also cool air for the lungs, cool air and cool water for the skin, the softer emotions for the nervous system. As an evidence of the great influence of this system, at least of the brain and its functions or mind, over the desire for drink, we

know that sleep will suspend the cravings of this stimulations, but the digestive sense is not so latter and even entirely remove it.

Next to simple water, and that with the addition THUNDER AND LIGHTNING. The surof a little mucilage, the fluid, with a slightly saline face of the earth, and of all bodies with which we impregnation, is useful in moderating thirst. Ani- are acquainted, is supposed to contain or possess a mals, especially herbivorous quadrupeds, usually so power of exciting or exhibiting a certain quantity particular in taking no other drink but simple of an exceeding subtile agent called the electric water, will often drink with avidity from a saline fluid. The quantity usually belonging to any surspring or lick. The vessels called absorbents, face is called its natural state, and it then produces which drink up fluids to be carried into the circu- no sensible effects; but when any surface becomes lation, to dilute the blood and aid in the various possessed of more, or less, than its natural quansecretions, are usually very careful to exclude tity, it is electrified, and it then exhibits a variety foreign matters; but when they allow the entrance of peculiar and surprising phenomena ascribed to of these, it is saline substances, in minute propor- the power called electric. tions, in preference to all others.

The most advantageous form that can be given to lightning rods appears evidently to be that of a very sharp cone; and the higher it is elevated in the air, other circumstances being the same, the more its efficacy will be increased, as is clearly proved by the experiments with electrical kites, made by M. Romas and M. Charles.

From the similarity between lightning and the | been quenched by the rain; the crops and fruits electric fluid, it had long been supposed, that they penetrated by new warmth, ripen more rapidly, were one and the same thing; but it was left for and man silently adores the great Being whose Dr. Franklin to prove the truth of this supposition. power has been displayed. When the clouds and the different terrestrial objects, over which they pass, are charged, one positively and the other negatively, in the passage of this fluid from the former to the latter, there is presented what we call lightning. So likewise, where two clouds come in contact, differently charged, the same result takes place. Thunder is the report which accompanies the taking place of this electrical union. It is occasioned by the rarefaction or displacing of the air, and its sudden return to its original position. Thunder and lightning bear the same relation to each other, as the flash and report of a cannon.

It has not been accurately ascertained how far the sphere of action of a lightning-rod extends, but, in several instances, the more remote parts of large buildings on which they have been erected, have been struck by lightning at the distance of three or four times the length of the conductor from the rod. It is calculated by M. Charles, that each lightning-rod will effectually protect a circular space, whose radius is twice the heighth of the conductor; and they are now attached to buildings according to this principle.

A current of electric matter, whether luminous or not, is always accompanied by heat, the intensity of which depends on the velocity of the cur rent. This heat is sufficient to make a wire red hot, or to fuse or disperse it, if sufficiently slender

metal, on account of its large mass. It is by the heat of the electric current, as well as by that disengaged from the air, condensed by the passage of the lightning through it, when not conveyed by a good conductor, that buildings struck by it are frequently set on fire.

The experiment of Dr. Franklin, to prove, that lightning and electricity were the same thing, was exceedingly simple. He took a boy's kite covered with a silk handkerchief instead of paper, and then fastened some wire to the upper part which served to collect and conduct the fluid. When he had raised this machine into the atmosphere, he drew electric fluid from the passing clouds, which descended through the flaxen strings of the kite as a conductor, and was afterwards drawn from an iron key, which he tied to the line at a small dis-but it scarcely raises the temperature of a bar of tance from his hand. This important discovery immediately led to the formation of conductors to secure buildings from the effects of lightning. Thunder is more or less intense, and of longer or shorter duration, according to the quantity of air acted upon, and the distance of the place where the report is heard from the point of the discharge. In summer when the earth is dry, and the day is warm, droughty and serene, the atmospheric electricity increases from sunrise till mid-day, when it arrives at its maximum; it then remains stationary for two hours, and afterwards diminishes until the fall of the dew. Towards midnight it revives, to be again almost entirely extinguished. In winter, the maximum of electricity is at eight o'clock in the evening, being weaker through the day. In all these variations atmospherical electricity seems very exactly to follow up the developement of hydrogen gas, which is more or less considerable at different periods of the day.

No instance has yet occurred of an iron bar rather more than half an inch square, or of a cylinder of the same diameter, having been fused, or even heated red hot by lightning. A bar of this size would therefore be sufficient for a lightning rod; but as its stem ought to rise from 15 to 20 feet above the building, it would not be strong enough to resist the action of the wind, unless the lower part were made much thicker.

An iron bar about three quarters of an inch square, is sufficient for conductors. It might even be made still smaller, and consist merely of a wire, provided it were connected at the surface of the ground with a bar of metal, about half an inch Electrical phenomena are more prevalent in square, immersed in water, or in a moist soil. The some quarters of the globe than others. Towards wire indeed would pretty certainly be dispersed the poles, the disengagement of hydrogen gas is ex- by the lightning, but it would direct it to the tremely scanty, and there is also no continual friction ground, and protect the surrounding objects from between the earth and the atmosphere. Thunder, the stroke. However, it is always better to make accordingly, is rarely observed in those regions; the conductor so large as not to be destroyed by it is only a weak decrepitation. As we advance the stroke; and the only motive for substituting a towards the equator, hydrogen gas becomes more wire for a stout bar is the saving of expense. abundant, and at the same time storms are most The noise of the thunder generally occasions violent. It is under the equinoctial line that we much alarm, although the danger is then passed; meet with that vast extent of sea, where thunder it is over, indeed, on the appearance of the lightstorms almost constantly prevail.

Storms, notwithstanding the calamities which they frequently occasion, and which the thunder rod cannot infallibly prevent, deserve to be considered as one of the greatest benefits our Creator has bestowed. They diffuse freshness through the atmosphere when it is in a confined and sultry state; the plants resume their lively green, the flowers raise their drooping heads, when their thirst has

ning, for any one struck by it neither sees the flash nor hears the report. The noise is never heard till after the flash, and its distance may be est mated at so many times 1136 feet as there are seconds between the appearance of the lightning and the sound of the thunder.

Lightning often strikes solitary trees, because, rising to a great height, and burying their rocks deep in the soil, they are true lightning rods; and

they are often fatal to the individuals who seek them for shelter, since they do not convey the lightning with sufficient rapidity to the ground, and are worse conductors than men and animals. When the lightning reaches the foot of the tree, it divides itself amongst the neighboring conductors, or strikes some in preference to others, according to circumstances. Sometimes it has been known to kill every animal that had sought shelter under the tree; at others, only a single one out of many has perished by the stroke.

A lightning-rod, on the contrary, well connected with the ground, is a certain security against the effects of lightning, which will never leave it to strike a person at its foot; though it would not be prudent to station one's self close to it, for fear of some accidental break in the conductor, or of its not being in perfect communication with the ground.

When the lightning strikes a house, it usually falls on the chimneys, either from their being the most elevated parts, or because they are lined with soot, which is a better conductor than dry wood, stone, or brick. The neighborhood of the fireplace is consequently the most insecure spot in a room during a thunder storm. It is best to station one's self in a corner opposite the windows, at a distance from every article of iron or other metal of any considerable size.

Persons are often struck by lightning without being killed; and others have been wholly saved from injury by silk dresses, which serve to insulate the body, and prevent the access of the electric

matter.

The stem, or part of the rod above the building, should be a square bar of iron, tapering from its base to the summit, in the form of a pyramid. For a height of from 20 to 30 feet, which is the nean length of the stems placed on large buildings, the base should be about two and a half inches

square.

Immediately above the cap, the stem is rounded for about two inches to receive a split collar, with a hinge and two ears, between which the extremity of the conductor of the lightning rod is fixed by a bolt. Instead of the collar, we may make use of a square stirrup, embracing the stem closely. The stem of the lightning rod is fixed on the roof of buildings according to circumstances. If it is to be placed above a rafter, the ridge must be pierced with a hole through which the foot of the stem passes, and is steadily fixed against the king post by means of several clamps. This disposition is very firm, and should be preferred if circumstances admit of it.

If the stem be fixed on the ridge, a square hole must be made through it of the same dimension as the foot of the stem; and above and below we fix, by means of bolts, or two bolted stirrups, which embrace and draw the ridge together, two iron plates about three quarters of an inch thick, each having a hole corresponding to that in the woodwork. The stem rests by a small collet on the upper plate, against which it is strongly pressed by a nut, made to screw on the end of the stem against the lower plate.

Lastly, if the lightning rod is to be fixed on a vaulted roof, it should be terminated by three or four feet, or spurs, which must be soldered into the stone, with lead, in the usual manner.

The lower part of the conductor should be an iron bar or rod about three quarters of an inch thick, reaching from the bottom of the stem to the ground. It should be firmly united to the stem by means of a collar, screw, or bolt, and its several parts should be connected together in a similar manner. After penetrating into the ground for about two feet it should be bent at right angles to the wall of the building, and after being carried in that direction for twelve or fifteen feet, it should be made to communicate with a well, drain, aqueduct, or permanently moist earth. If the soil be dry, it should extend to the depth of twelve or fifteen feet; and to secure it from rust, it should be surrounded with charcoal, which is indestructible, and which, while it preserves the iron, facilitates the passage of the electricity into the ground by its conducting property.

Both the bottom and top of the lightning rod are sometimes made to terminate in several branches, and its efficacy is thus increased. It is also recommended to connect with the lightning rod any large masses of iron that may be in the building, as metal pipes and gutters, iron braces, &c.; without this precaution the lightning might strike from the lightning rod to the metal, especially if there happened to be any interruptions in the former, and thus occasion serious injury to the building, and danger to its inhabitants.

Iron being exposed to rust by the action of the air and moisture, the point of the stem is liable to become blunt; to prevent this, a portion is cut off from the upper end, about 20 inches in length, and replaced by a conical stem of brass or copper, gilt at its extremity, or terminated by a small platina needle, two inches long; or, instead of a platina needle, one of standard silver may be substituted, composed of nine parts of silver, and one of copper. The platina needle should be soldered with silver solder to the copper stem; and to prevent its separating from it, which might sometimes happen notwithstanding the solder, it is secured by a small collar of copper. The copper stem is united to the iron one by means of a gudgeon which screws into both. If the gilding of the point cannot easily be performed on the spot, nor the platina be readily obtained, we may dispense In the case of powder magazines, the lightning with both without any inconvenience, and employ | rod should not be attached to the building, but to only a plain, conical, copper stem. Copper does not rust in the air to any considerable depth, and even if the point becomes somewhat blunt, the rod will not thereby lose its efficacy.

Below the stem, three inches from the roof, is a cap, soldered to the body of the stem, and intended to throw off the rain water, which would flow down the stem and tend to injure the building.

poles eight or ten feet from it. If the building be large, several should be used, arranged according to the rule, that a lightning rod may be considered as protecting a circular space whose radius is twice the height of the rod. If the magazine be in a tower or other very lofty building, it may be sufficient to defend it by a double copper conductor without any stem. As the influence of this con