74

that idea.' The truth is, we believe, that Shakspeare copied from Nature, and not from any monumental figure: for it is well known to the medical world that, in certain pining disorders, that peculiar hue of "green and yellow" generally tinges, in a very striking manner, the female countenance. The author's remarks on Self-importance will generally excite a smile of approbation :

I sometimes meet a man so stately in his deportment, so haughty in his look, with such an air of defiance in his whole manner, that I shrink from his appearance, and feel myself annihilated in his presence. Yet, on recovering from my dismay, and reflecting on the limited power and capacity of every human being, I find, probably, on inquiry, the real character of this illustrious personage: that his pompous air conceals a mean spirit, and that the solemn countenance is only a veil for his ignorance and insignificance.

'Such are many of those colossal figures who seem to "bestride the world, and under whose legs, as it were, we petty mortals must peep about," to find a loop hole to pass by them, without being crushed against the wall, or jostled into the kennel.

One man, whom I have met, perhaps, at a third place, assumes a reserved and distant air, lest I should claim him as an acquaintance. Another man, with eyes fixed, looks strait forwards, and though our elbows almost touch, seems unconscious that any one is near him, or at least worth his notice.

A third is near-sighted, and though we have met, perhaps, on various occasions, has not the honour to recollect my name. All these are different stratagems of pride and self-importance, which, though not reducible to the precise rules of quarrelling, "like the lie direct," and for which we can call a man to account; yet may and ought to be resented, or rather treated with the contempt which they de

serve.

• I remember a stout fellow with a most terrific countenance, who, if he met a man strutting along in sublime contemplation of his own importance, and a sovereign contempt of all around him, he would, on a sudden, run up to him, turn his large white eyes upon him, and cry, Boh! This, it may be supposed, often involved him in a scuffle, or rough rencounter; but generally raised a laugh at the expence of the haughty despot.

A proud look is an insult on the public. Pride was not made for man: nor for woman neither.'

The chearful little essay on the tax on Port Wine will amuse the reader. The author suggests an expedient under this heavy impost:

But, after all, supplies must be raised, and taxes be imposed on the necessaries as well as luxuries of life: let us then make the best of what cannot be avoided.

Perhaps, the dearness of wine may be attended with the same beneficial effects as the late scarcity of bread; and make us more sparing in the use of it, or find some substitute in its room.

• Let

Let the ladies then, after dinner, be content with three glasses, the number of the Graces; and the gentlemen with nine, the number of the Muses.'

If we rightly recollect, Sir William Temple was not so bountiful as Mr. Graves in his allowance to the gentlemen. He allotted a third glass to good humour, and a fourth to our enemies. Perhaps Mr. Graves's system, although it is founded on the proportions of Heathen Mythology, will be more commonly approved.

The second portion of the volume consists of a variety of compositions in verse, intitled-poetical, panegyrical, humorous, miscellaneous. In so multifarious a collection, it is difficult to give any general character of the whole. Indeed, it will be apparent to the reader that many of these compositions are the unlaboured effusions of a gay and vivacious mind, and are not so much intended to display the poet, as to amuse the composer, and to furnish recreation for his friends, who can be pleased without exercising the severity of a critic.-At the same time, we must do the author the justice to add that several of these pieces have merit considered as poetry, and will be commended even by the fastidious critic. We give an extract from the humorous collection:

• When naked all, like Eve and Adam,
Your Joan might be as good as Madam ;
And, tillage then the only trade,
We all had learnt to use the spade.
But, tho' mankind are still the same,
And equal rights by nature claim;
Yet, if no social laws existed,
And every man did what he listed;

If all mankind must dig or spin,

You'd have no covering but your skin.
For, who would weave, or be your taylor?
Who'd be a soldier or a sailor?

shelves?

Who'd make your tables or your
'Troth! you must make them all yourselves.
Let each man then assist his neighbour,
And each perform some useful labour :-

* A fanatic priest in the reign of Richard II., who by his sedi

tious sermons and rhymes, without reason, sowed the seeds of Wat Tyler's Rebellion.'

Thus

Thus various arts would be invented,
And those, now poor and discontented,
Might soon grow rich, by labouring more;
While lazy folks must needs be poor :
For why should they, who take no pains,
Rob others of their honest gains?
While some obey, and some command,
And each man lends an helping hand;
While those best skill'd, the vessel steer,
Each may be happy in his sphere.

In short, 'tis evident, you see,
That different ranks there needs must be;
There must be then, say what you can,
That dreadful thing-a Gentleman!'

We observe repeatedly in these poetical pieces the expres sion I wont" without the auxiliary was. We shall not, however, detain our readers with any verbal or trivial remarks, but conclude with recommending this sensible and good-humoured volume to general notice.

Mans

ART. XI. An Experimental Inquiry into the Nature and Propagation of Heat. By John Leslie. 8vo. PP. 570 and Plates. 149. Boards.

Maw man. 1894.

T
HE philosophical world is by no means unacquainted with
the name of the author of this volume, although no sepa-
rate detail of his labours in the cause of science had previously
issued from his pen. We are glad, however, to see that he
has at length turned his attention to the production of an ela-
borate work; and that he has selected for investigation the im-
portant subject of Heat, which has lately been much discussed,
and which forms so essential a part of our chemical and phi-
losophical knowlege. The publication before us has already at-
tracted much notice from scientific men: notice to which we
conceive it to be fully intitled; and every degree of which,
that is within our power to assign to it, we shall now bestow
on it by entering into a copious and patient analysis of its con-
tents. In the execution of this duty, we shall follow, in part,
the plan of the author; first stating the experiments, and then
explaining the theory of which they are the ground-work. A
previous description of the apparatus, however, is necessary;
and we shall give it in Mr. Leslie's own words:

The principal articles of the apparatus were specula or reflectors made of tinned iron. Of these I had several, of different dimensions; from twelve to about fourteen inches in diameter, and with a depth of concavity from 1 to near 2 inches. It cost me no small trouble to obtain what I wanted. I had to make repeated trials before I could

find an artist skilful enough to execute the reflectors with any told rable precision, or who was disposed to listen to my directions. But by dint of perseverance, my sanguine wishes were at length gratified. The reflectors were hammered out of block-tin, and highly finished, exhibiting an admirable brightness, smoothness, and regularity of surface. Aware that the aberration from the focus in reflection must be very considerable when large segments of hollow spheres are used, I sought to procure the parabolic figure. I 'ormed thin slips of mahogany with great accuracy, into segments of parabolas of different sizes, to serve as gages for the workman; and with some dexterity, and the frequent changing of the hammers, the reflectors were fashioned to fit those shapes with surprizing exactness. As it was my object to obtain the most powerful relictors that could be made in this way. I was at pains to procure tin-plates of the largest dimensions, and to have them hammered to the greatest depth of concavity that the metal would bear without being fractured. Exposed to the direct light of. the sun, these reflectors collected the rays into a pretty distinct focus, scarcely exceeding half an inch in diameter, so that the whole errors of the figure did not occasion a deviation of more than a quarter of an inch on either side. And though the sun's image was therefore one hundred times more diffuse than if the figure had been perfectly true, yet the effect of those reflectors was very remarkable, and even comparable with that of concave mirrors; for bits of wood or cloth, held in the focus, were burnt through or set on fire, in a few seconds.'

The second part of the apparatus, intended to contain hot water, consisted of hollow tin cubes, formed exactly, and hammered to a smooth and bright surface:

These canisters had an orifice at the middle of the upper side, from half an inch to an inch in diameter, and the same in height, fitted to receive a cap through which was inserted a thermometer, whose bulb might reach nearly to the centre of the water. The cubes were of different sizes; of three, four, six, and ten inches. In two of them, namely, those of four and ten inches wide, the lid was not soldered, but could be adapted or removed at pleasure; and there being no occasion for an aperture, the stem of the thermometer was passed through a short pipe.'-

One side was constantly kept clean and bright, the opposite one was covered with writing paper pasted to it, or was painted over with a coat of lamp-black, mixed up with as little size as would make it take a body. The other sides, being allotted for miscellaneous service, were, according as the case required, coated indifferently with tin foil, or coloured papers, or different pigments, or had the nature of their surface changed by mechanical or chemical agents.'

The canisters were placed on stools, so contrived as to have their centres in the horizontal axis of the reflector.

The chief instrument in the apparatus is the differential ther mometer: which consists of a tube bent into the form of the letter U, each extremity being closed by a hollow ball, and sulphuric acid tinged with carmine being introduced into the tube. Each

leg

Jeg of the instrument may be from three to six inches in height, and the balls from two to four inches apart. The lower end of the syphon is cemented into a wooden base, so that the two balis may be on a level with the centre of the speculum.

A moment's attention (says the author) to the contruction of this instrument will satisfy us that it is affected only by the difference of heat in the corresponding balls, and is calculated to measure such difference with peculiar nicety. As long as both balls are of the same temperature, whatever this may be, the air contained in the one will have the same elasticity as that in the other, and consequently the intercluded coloured liquor, being thus pressed equally in opposite di rections, must remain stationary. But if, for instance, the ball which holds a portion of the liquor be warmer than the other, the superior elasticity of the confined air will drive it forwards, aud make it rise in the opposite branch above the zero, to an elevation proportional to the excess of elasticity or of heat. It is easy, after the mode practised in the case of the hygrometer, to fix the magnitude of the degrees for any particular instrument, and, if it were expedient, other methods might be proposed which are applicable to the present instance. The interval between freezing and boiling water being distinguished into an hundred equal parts called centigrade, each of these subdivided decimally constitute the degrees which I employ, and which, following up the same system of nomenclature, would be termed milligrade. With the measures which I have stated, cach differential thermometer will contain from 100 to 150 degrees. I would observe, however, that such graduation is seldom positively required, and that, in most cases, it is less important to know the absolute quantities of heat than their relative proportions. I need scarcely add that I had a variety of those differential thermometers, of different sizes, and of some diversity of forms, adapted for particular occasions.'

We now proceed to relate the experiments.

The apparatus being in a close room without a fire, the canister was placed opposite to the reflector; and one of the balls of the thermometer (called, for the sake of distinction, the focal ball) was placed in the focus of the reflector. Almost immediately, the coloured liquor rose. When the blackened side of the canister was opposed to the reflector, the effect was denoted by ico degrees; when a side covered with paper, by 98; when a side covered with crown glass, by 90.

Any one of these experiments, then, clearly manifests an accumulation of heat in the focus of the reflector; and, compared together, they indicate a slight alteration of effect attendant on the quality of the substance, of which the side of the heated canister is formed.-Present to the reflector the polished side, or any side covered with tin foil, and the liquor in the differential thermometer sinks to 12 degrees. Here, then, is a manifest difference of effect; and, without trespassing against the cautionary precepts of inductive philosophy, we may safely say

that