that it gave out the whole excess of its heat, and that it issued out exactly at the temperature of the water of the calori

meter.

Hence we concluded that the heat given out by the gases was equal to the excess of their temperature at their entry into the calorimeter, such as we determined it, above that of the calori

ineter.

§ IV.-Influence of the Tube which served to heat the Gases upon the Temperature of the Calorimeter.

An inconvenience attended the shortening of the intermediate tube between the vapour tube and the calorimeter. The calori meter was heated directly by communication, independent of the heat which it received from the gas which circulated in its inte rior. Now, as notwithstanding all the precautions that could be taken to measure the heat received by the calorimeter from that cause, some error might have been committed in the measurement, it was necessary to make it as little as possible, that it might be neglected without risk. On this account we employed for that part of the tube a tube of glass, because that substance is a bad conductor of heat. This tube, 0.8 inch in length, and 0.3 inch in diameter, was fixed to the apparatus in the following manner, a little complicated in appearance, but very easily executed, and having the great advantage of rendering lutes of

no use.

The sides of our calorimeter are strengthened below by a pretty thick plate of copper, about 0-8 inch high, firmly soldered on, and covering nearly one-half of the circumference, as may be seen in fig. 6, which represents a horizontal section of the calorimeter through its lower part. This plate has fixed to its two extremities two rods, bb, VV', six inches long, and cut half their length into the threads of a screw, upon which are fixed the nuts, C, C'. The middle of this plate is pierced with a hole, dd, which coincides with the orifice by which the inferior part of the serpentine opens outwards. Round the hole is a flat place, ff, destined to receive a piece of leather.

Fig. 7 represents the extremity of the tube filled with vapour, which serves to heat the gases. This extremity is of copper. The plate, E E, which terminates it, is pretty thick, and pierced in its middle with an opening, II, communicating only with the interior tube, which contains the gas. This opening is surrounded externally with a flat place, LL, which receives a round piece of leather. Immediately in the neighbourhood of the terminal plate is the tube R S, which opening into the inside of the vapour tube, allows the vapour and the condensed water to escape, and carries them to a distance from the calorimeter, It

is the same tube that is represented by GI in the horizontal section of the apparatus, fig. 5.

M M, N N, are two oval plates, pierced in their centre by a circular opening, which receives the vapour tube, to which they are firmly fixed. At each of their extremities is a hole, sufficiently large to give passage to the rods, bb, V′′, fixed to the calorimeter, and represented in fig. 6.

1

It is easy to see that when the extremity of the vapour tube is presented to the calorimeter, and the metallic rods are made to pass through corresponding openings in the wooden disks, M M, N N, the opening, II, of the gas tube will be exactly opposite to the opening, dd, of the serpentine. If we interpose between the two openings a tube of glass of the requisite size, and such that its extremities, ground with care, press against the disks of leather which cover the flat faces, ff, LL; and if, by means of the nuts, C, C', we force the extremities of the vapour tube to approach as near as possible to the calorimeter, then the tube of glass firmly fixed between the two disks of leather will esta→ blish a communication between the gas tube and the calorimeter, and will prevent all gas from escaping in any other direction.

In describing our apparatus we have said that the calorimeter was in a different room from that of the rest of the apparatus, and that the communication took place by means of a hole made in the door (fig. 5). As a part of the vapour tube was in the same room with the calorimeter, it was screened from the effect of radiation by covering the hot tube with a box of tin plate, properly disposed to allow no radiant heat to pass, and that the air which surrounded this tube should have no communication with that which surrounded the calorimeter.

Notwithstanding all these precautions we could not prevent the calorimeter from being a little heated by the vapour tube by immediate communication. We endeavoured to determine to how much that cause of heat amounted. We have ascertained that when it acted alone it amounted to 3.1° (54° Fahrenheit); and we think we may, without sensible error, reckon it at 2·5o (4 Fahrenheit) when the calorimeter was heated likewise by the current of hot gas.

The preceding details, perhaps, will be thought rather long; but we considered it improper to omit them, because they will enable the reader to appreciate the accuracy of our results. We hope that the experiments which we shall next describe will merit the confidence of philosophers and chemists.

(To be continued.)

* See note 1 at the end of this paper.

ARTICLE IX.

Analysis of the Chyle of the Horse. By M. Vauquelin.*

M. VERRIER, Clinical Professor at the Veterinary School of Alfort, had the goodness to procure me, at my request, the chyle of two horses, which he destroyed by blowing air into the left jugular. These horses, though exhibiting some symptoms of the glanders, were, notwithstanding, in good condition, and had the appearance of good health. One of them, aged four years, was a stallion; the other, aged eight years, was a gelding. Both of them had eaten abundantly of hay and oats before their death. They were opened immediately after death, and the thoracic duct was tied near its insertion into the right axillary.

The first of these horses furnished, by means of a puncture towards the middle of the thoracic duct, a considerable quantity of chyle, of a red colour, but less intense than that of blood. There was obtained, likewise, by puncturing one of the sublumbar branches, a considerable quantity of chyle as white as milk.

The second horse, by puncturing the middle of the thoracic duct, yielded a quantity of reddish chyle; but it was not prac ticable to puncture the sublumbar branches, and procure white chyle, as was done with the first horse,

As 1 examined each of these portions of chyle separately, I shall, in order to be better understood, denote each by numbers, in the order according to which I propose to treat of them. I shall call No. 1 the portion of chyle drawn from the middle of the thoracic duct of the first horse; No. 2, the white portion of chyle furnished by the sublumbar branches of the same animal; and No. 3, the chyle obtained from the thoracic duct of the second horse.

When we examine what anatomists and physiologists have said of chyle, we find very little that can throw light upon its chemi cal nature. They have all described, with more or less exactness, its physical characters, and the modifications which it undergoes in different circumstances. I shall here give a short abstract of their remarks upon this subject.

Lister observed chyle swimming, like a species of oil, on the surface of blood and of serum. Wepfer observed that a kind of cream formed on the surface of chyle. Bourdon, Pecquet, Bartholin, Monro, &c. announced the coagulation of chyle, both in the vessels which contain it, and in the open air. Bohn, Berger, Ash, described butyraceous globules swimming in an

* Translated from the Annales de Chimie, vol. lxxxi. p. 113.

aqueous liquid. They conceived that chyle contains a cheesy matter, which they considered as more earthy than the other constituents, and by the precipitation of which they accounted. for the calculous concretions found in the reservoir of the chyle by Schars, in the thoracic duct by Ledran, and in the vessels by Goëlik. Mart, Musgrave, and Lister, announced that indigo, mixed with the food, and given to animals, tinged the chyle of a blue colour; and this observation was confirmed by Baller, Gould, and Felix. Mattei says that he communicated a red colour to chyle by giving beet to animals for food. Several observers speak of a green colour in the chyle of herbivorous animals. M. Hallé, to whom we are indebted for several interesting experiments on the same subject, never observed in the chyle of dogs to which he had given pastry coloured blue, red, and black, by means of vegetable substances, any trace of these colours. The physical properties which we have observed in the chyle of the horse are very similar to those which M. Hallé observed in the chyle of dogs. Such are the principal facts which are to be found in authors respecting chyle. I now pass to the analysis.

CHYLE, No. 1.-Physical State.

This portion of chyle, of a red colour, was coagulated when brought to me. It contained a small quantity of liquid, less coloured than the coagulated portion, which was itself of a much lighter colour than blood. It was red, and semitransparent, like currant jelly badly boiled; yet its consistence was pretty firm.

Chemical Examination of the Liquid Portion, or the Serum of the Chyle No. 1.

1. This liquid quickly restored the blue colour to litmus, reddened by acids; which proves that it contained an uncombined alkali.

2. Heat and acids coagulated it into a greyish white mass.

3. Alcohol likewise occasions an abundant coagulation in it.. The coagulum is white, but acquires a reddish tint by desiccation. It becomes at the same time transparent, and exbibits a vitreous fracture. When thus dried it decrepitates, and melts on red-hot coals, exhaling an empyreumatic ammoniacal odour.

This coagulum dissolves in caustic potash; but the liquor remains milky, and does not become transparent, as happens to a solution of the albumen of blood in the same circumstances. The alkaline solution is precipitated by acids, and at the same time there exhales from the mixture an odour of sulphur, which has some analogy to the smell perceptible in stables.

CHYLE, No. 2.-Physical State.

This portion of chyle was white and opake, like milk. It contained a coagulum equally white and opake.

After having separated the liquid portion from the coagulum, I washed the latter, and set it aside. The reader will find an account of its properties hereafter.

The Liquid Portion.

This portion, drawn from the sublumbar branches, presented the same properties as the liquid from the red portion of chyle, excepting as to colour. It was coagulated by heat, by acids, by alcohol, the precipitates were redissolved by the alkalies, and the solution remained milky, like the solution of the precipitate from the coloured portion of the same chyle.

The portion of white chyle treated with boiling alcohol was entirely coagulated, as I have mentioned above; but the alcohol retains in solution a small quantity of matter, a part of which it deposites, on cooling, in the form of flocks; but a portion remains in solution, as is shown by the addition of water, which renders the alcohol milky.

Though I have been able to procure only a quantity of this matter insufficient to ascertain its nature exactly, yet I think myself entitled to conclude that it is a species of fat, the insolubility of which in the alkalies shows it to be analogous to what I found in the matter of the brain.

It is, without doubt, this fatty matter which, by its presence, prevents the albumen, in separating from the coagulum, from becoming transparent, like that of blood. It likewise occasions the albumen precipitated by alcohol to remain opake after desiccation. It dissolves in boiling alcohol, and is deposited as the alcohol cools, and it gives the alcohol the property of becoming milky when mixed with water.

As to the matter coagulable by heat, acids, alcohol, &c. there can be no doubt, I think, that it is albumen. It forms the greatest part of the chyle.

Thus the liquid parts of the two portions of chyle, Nos. 1 and 2, are of the same nature, if we except the red colour, which does not exist in the chyle of the sublumbar branches, though that chyle contains the materials proper to produce it.

Examination of the Coagulum formed spontaneously in the cos loured Portion of Chyle, No. 1.

To obtain the substance which had produced the spontaneous coagulation of that portion of chyle, I washed the mass with water, in the same manner as is done with the coagulum of blood when we want to obtain the fibrin.