tries them. The rollers will be found of great service where capstans of the common form are used, and in that case the stantion of the roller should not be so high as the one fitted in the Argo, but just of sufficient length to allow the roller to traverse clear of the deck, which would give more room for the turns of the messenger round the capstan, and make the support of the roller greater. But the expense, and occasion for them, will be totally avoided by the trifling alteration being made in the capstans.

I am, &c.

(Signed)

BENJAMIN HALLOWELL.

Experiments on the Cause of the Coagulability of saponaceous Solutions, and Indication of a Method of discovering the Quality of Soap. By M. VERBERT,

From VAN MONS' JOURNAL DE CHIMIE.

NOTHING is frequently more difficult than to dis

cover, by sight, the quality of white soap, as this substance may be composed of very different ingredients, and still preserve the same exterior appearances.

A research which I made into the nature and qualities of soap, furnished me with a method of distinguishing the nature of the elements composing that substance. The following are some of the experiments that led me to this result.

In a preceding experiment, intending to dissolve one part of white soap, which appeared to be of good quaVOL. II.-SECOND SERIES.

S

lity a

lity, in eight parts of spirit of wine, at 26° of Baumé, instead of a limpid solution I obtained an opaque liquor, resembling jelly when cold. A more perfect solution was not effected by 64 parts of fresh spirit, which I added to it. A similar solution was produced by the same soap with alcohol, common spirits of wine and water. One part of this jelly communicated its character to four or five parts of the spirit of soap. This jelly was rendered limpid by heat: I submitted it to distillation in a glass retort, and obtained a thick greasy residuum, soluble in water, but not transparent.

Oxysulphuric acid diluted with water and other oxygenated acids, separated from the jelly a greasy dirty matter, which stuck to the fingers. It is well known that oxygenated acids separate the oil in its natural state from soaps that have been properly prepared. Having prosecuted this labour no farther at the time, I resolved to resume it, by endeavouring to discover, by synthetical researches, the composition of this gelatinous soap.

1. I made a soap by uniting, by trituration in a glass mortar, two parts of olive oil to one part of caustic alkaline ley, newly prepared. This soap was very perfect.

2. To ascertain whether an incorporation of starch might not perhaps have been the cause of the formation of the jelly, I mixed one part of that substance in powder with six parts of the soap just described, before it acquired a consistence: but a warm solution of this soap in spirits of wine precipitated the starch.

3. I incorporated with one part of ley two parts of melted tallow and one-fourth part of starch. In the space of two or three hours it formed an extremely hard soap,

which produced a jelly with spirits of wine and water. This jelly, with the last-mentioned liquid, in the proportion of one-eighth was opaque; with one-fourth it formed an apparently excellent soap: fifteen parts, dissolved in eight parts of water, communicated the gelatinous consistence to 120 parts of spirits of wine. An aqueous solution of this soap from tallow was milky, like an emulsion.

4. I made the soap (No. 3) without adding starch. The produce was the same, but the jelly which it formed had less consistence.

5. Ley and grease combined in the proportion of one to two yielded a very white and hard soap, which rectified spirits of wine dissolved when warm, by separating from it some flakes of a whitish matter, but the solution of which assumed the character of jelly when cold. Its aqueous jelly was however less firm, and a solution of it not so white as with the soap made of tallow,

These different results confirm what Struve had before hinted relative to the cause of the congelation of saponaceous solutions. In spirits of wine they furnish a certain re-agent for ascertaining the quality of a soap by pointing out the oily or sebaceous nature of the fat substance of which it is composed. I have likewise observed that soap made of tallow requires, for congealing, twice as much spirits of wine as that made of grease.

On the Wax Tree of Louisiana and Pensylvania. By CHARLES LOUIS CADET, of the College of Pharmacy.

From the ANNALES DE CHIMIE.

A Multitude of plants, as the croton sebiferum, the tomex sehifera, of Loureiro, the poplar, the alder, the pine, yield by decoction a concrete, inflammable matter, more or less resembling tallow or wax; that is to say, a fixed oil, saturated with oxygen. The light down, which is called the flower of fruits, and which silvers the surface of plumbs and other smooth-skinned fruits, is wax, as M. Proust has demonstrated. But the tree which affords this substance in the greatest abundance, that which ou more than one account deserves the attention of agriculturists, chemists, physicians, and commercial men, is the myrica cerifera, or wax-tree.

We find in the History of the Academy of Sciences for the years 1722, and 1725, that M. Alexandre, a surgeon, and correspondent of M. Mairan's, had observed in Louisiana, a tree of the height of a cherry-tree, having the appearance of a myrtle and nearly the same smell, bearing a berry of the size of coriander seed. These berries, of an ash-grey colour, contained, he said, a small, hard, round kernel, covered with a glossy wax, which is separated by boiling the berries in water. This wax is drier and more friable than the common wax. The natives of the country make candles of it. M. Alexandre added, "this berry is commonly charged with a beautiful lake colour, and stains the fingers if merely squeezed between them, but only at a particular time of the year."

M. Alexandre likewise discovered, that the liquor in which the berries have been boiled, when poured away and evaporated

evaporated to the consistence of an extract, having previously skimmed off the wax, was capable of stopping the most violent dysenteries.

The useful properties belonging to this tree should induce scientific men to make enquiries, for the purpose of discovering what varieties there are of this vegetable, and what care is requisite for its cultivation. It appears to have been considered for a long time as merely an object of curiosity.

Linnæus, in his System of Vegetables, mentions only the Virginia wax-tree, myrica cerifera, with lanceolated, or rather dentated leaves, with a stem like a tree.

I wrote to M. Ventenat, requesting him to inform me, whether there are several species of it: he was so obliging as to answer me, that Ayton distinguished two, namely;

1. The myrica cerifera angustifolia, which is a native of Louisiana. This is a delicate tree, is reared with dif ficulty in our green-houses: its seed is smaller than that of the other.

2. The myrica cerifera latifolia, which grows in Pensylvania, Carolina, and Virginia. It is not so high as the other, and thrives perfectly well in France.

Both of these myricæ are cultivated in the Museum of Plants, and in the garden of Messrs. Cels and Lemonier. M. Michault admits a third species of myrica cerifera, which he calls dwarf war-tree. M. Ventenat thinks that wax may be obtained from all the myrice.

The authors who have treated of these trees at some length are, Marshall, translated by Leserme, Lepage, Duprat, and Toscan, librarian of the Museum of Natural History. A memoir inserted by the latter in his work entitled, L'Ami de la Nature, describes the manner in which the vegetable wax is obtained in the colonies.

"Towards