The expense of cultivating an acre of land by the plough, admitting one digging to be equal to three ploughings and harrowings, will be thus.

Three ploughings and harrowings, at 10s.....£1

10

18

2

£2 10

Thus it appears that the cultivation of an acre of wheat by the spade costs only five shillings more than by the plough.

In respect to wheat transplanted and sown on land worked by the spade, Mr. F. has no doubt that sowing is the best system; and that the advantage over the plough is from the deep and otherwise superior working of the land by the spade.

The average value of the produce of spade and plough culture .will be therefore found as follows.

By the spade 68 bushels per acre at 8s.

£27 S

By the plough 38 bushels per acre; this quantity
being a fair average on land better than that on
which Mr. F's. experiments were made, at 2s. 15

4

Being the advantage gained by the extra expense of five shillings.

Mr. F. being desirous of ascertaining how far and at what expense it may be practicable to work land by the spade by women, boys, girls, and feeble old men, he made an experiment for the purpose. The land was dug by girls, in two short spits, each of about five or

Busby's Hydraulic Orrery.

25

six inches deep, the one following the other, and moré effectually than by men at one spit of nine or ten inches deep. The wages paid these girls were 10d. per day. The cost, however, by the girls was per acre £2. 4s. 4d. that is 11s. 4d. per acre more than by men; but Mr. F. is satisfied that the superiority of the girls' work was worth the difference. The girls being unpractised in the use of the spade, was most probably the chief cause of the difference in the price. The spades they used were made for the purpose, being 9 inches long, 8 inches wide, and weighing, with the handle, about 4 lbs. Mr. F. states that 4 acres of land, such as that on which his experiments were made, are necessary to support a horse; which quantity, under the husbandry of the plough, will support nine persons, on the supposition of a common proportion of men, women, and children, by the spade cultivation, the same land will produce subsistence for more than twelve persons. These are im portant facts. I am, Sir, yours, &c.

CATO.

Nobel Inventions.

Hydraulic Orrery.

MR. Busby has devised a new and ingenious method of exhibiting the Solar system in motion upon a reservoir of water. The motive impulse is given to the different planets and their satellites by the re-action of several jets of water, issuing from syphons, by which means a silent and apparently spontaneous movement is produced, which exhibits the phenomena of the revolving orbs in a very simple and pleasing manner.

It is proposed by the inventor to construct his HYDRAULIC ORRERY as a scientific ornament upon any pool of

still water, in a park or pleasure ground. Models of the contrivance are now publicly exhibiting in the Strand, London, and the Society of Arts have adjudged Mr. Busby their gold Vulcan Medal for the invention.

Method of Analysing Vegetable Bodies. By A. B. GRANVILLE, M. D.*

THE first steps to be taken consist in examining the vegetable body physically; and next as to its chemical properties.

The colour, taste, flavour, smell, external appearance, botanical and physiological characters, state of aggregation, density, &c. belong to the former inquiry; while the experiments made with various tests on the infusion, decoction, extract, tincture of the bark, root, &c. under examination, belong to the latter.

In describing the substance and giving an account of the chemical experiments made with it, the same method should be adopted which has been followed during its analysis; and that method may be thus enunciated in the shape of general and aphoristic formulæ.

PHYSICAL CHARACTERS.

1. Colour of the bark, root, &c.

2 Nature of its epidermis.

3. Thickness of the bark and the epidermis, individually. 4. Mode in which they adhere together.

5. Whether any of the woody fibres adhere to the epidermis.

6. Smell, flavour, perfume, taste, permanent or evanescent.

* From the London Medical Journal for June, 1822.

Method of Analysing Vegetable Bodies.

27

7. Has the epidermis the same character with the liber ? 8. Is the bark easily powdered?

9. Does it readily attract moisture when exposed to the air?

10. Specific gravity of the bark.

11. Specific gravity when powdered.

CHEMICAL CHARACTERS.

a, Infusion.

1. A given quantity of the bark, coarsely powdered, infused in a sufficient quantity of cold water for a given number of hours.

2. Filter. Weigh the filtered infusion and the dry residuum on the filter. Examine the smell, taste, colour, and flavour of the infusion.

3. The filtred infusion should now be tried by

a. Isinglass.

b. Tartarized Antimony.

C. Prussiate of Potash.

d. Nitrate of Barytes.

e. Oxalic Acid.

f. Sulphate of Iron.

h. Sulphate of Copper.

i. Oxalate of Ammonia.

k. Gallic Acid.

7. Lime-water.

m. Tincture of Gall.

n. Turmeric Paper.

g. Supersulphate of Alumine. o. Litmus Paper.

4. Mark in writing the result of each experiment, and of every precipitate that follows: dry the latter, weigh

them, and keep them for further examination.

b. Decoction.

1. A given weight of the bark or root, coarsely powdered, boiled in a sufficient quantity of distilled water to the reduction of one-third.

2. Filter the decoction, mark its colour, taste, flavour, and perfume.

3. Test it with the same re-agents, and note the results;

and whether or not they be similar to those obtained in treating the infusion.

c. Extract.

1. The same quantity of bark, root, or plant, coarsely powdered, is to be subjected to the action of boiling water several successive times. The different decoctions added together are to be slowly evaporated in large vessels, to the consistence of extract. The extract to be weighed, the colour, taste, &c. noted.

2. Ascertain how much of the extract is dissolved in alcohol. Mark the taste, colour, and smell of the resulting tincture.

b. Emetine, gelatine, litmus, and turmeric paper, oxalic acid, carbonate of potash; and write down the result.

c. Sulphate of iron.

d. Nitrate of bary tes.
e. Nitrate of mercury.
f. Nitrate of silver.

g. Prussiate of potash.

5. If any residuum be left after treating the extract with alcohol, subject it to the action of distilled water, exposing it to a gentle heat at the same time, and trying the solution, if any with the above tests.

d. Alcoholic Infusion.

1. A given weight of the bark, root, &c. coarsely powdered, is to be infused into a known quantity of alcohol for a given number of days.

2. The smell, colour, taste, perfume, &c. of the resulting infusion are to be noted.

3 The infusion to be tested with

a. Distilled water.