MR. P. W. WATSON, of Hull has been engaged in the vicinity of London, since the spring of 1820, in collecting materials for a Dendrologia Britannica, or trees and shrubs that will live in the open air of Britain during the whole year, to be illustrated by original descriptions and coloured plates from living plants. One hundred and ten coloured octavo drawings by eminent artists, with occasional minute dissections are already completed of such hardy trees and shrubs as have not, a few excepted, been figured by recent respectable botanists.

A new society is about to be formed under highly auspicious circumstances for the encouragement and promotion of the science of entomology.

Gems, principally from the antique, with verse illustrations by the Rev. G. CROLY, M.A. drawn and etched by R. DAGLEY, are preparing for publication.

Mr. PONTEY's Practical Treatise on Rural Ornament, which deduces the science from well-known fixed principles, will appear in the course of the present month.

Mr. J. G. WALKER has just published a print of Mr. Stothard's celebrated picture of the senior scholars of Christ's Hospital delivering their orations on St. Matthew's day; report speaks highly of this engraving.

M. SIEBER is about to publish in two volumes, octavo, an Account of his Visit to the Island of Crete, with plates and maps.

Spade Husbandry. By an experiment Jately made to ascertain the difference between the use of the spade and the plough, the superiority of the spade has been unequivocally demonstrated. Of a field which was in beans last year and oats the year before, two ridges were dug and two ploughed alternately: the whole was sown on the same day;

a part both on the ploughed and dug being drilled with the garden hoe. The whole was reaped the same day; and, being thrashed out, the dug, sown broadcast, was to the ploughed, sown broadcast as fifty-five to forty-two. The dug and drilled was as twenty and a quarter to twelve and a quarter upon the ploughed and drilled. Besides the additional quantity of grain, there was also more straw, and the land was free from weeds.

Dr. ZIMMERMAN, professor of chemistry in the university of Giessen, has discovered that all the aqueous atmos▾ pherical precipitates or deposits, as dew, snow, rain, and hail, contain meteoric iron, usually combined in the same manner as meteoric stones with nickel. Most of the rains examined contained common salt, and a new or. ganic substance composed of hydrogen, oxygen, and carbon; this the Dr. calls Pyrine. Rain-water was often found also to contain various kinds of earths. From contemporary observations made on various eminences, the results are in favour of the opinion, that the stony meteoric masses are of telluric and not of cosmic origin.

A correspondent in the Annals of Philosophy will be obliged by any objection to the following definition of a straight line. A straight line is such as being divided or produced to any extent is still directed towards the same points. We do not desire to make this journal an arena of controversy, but we think this gentleman, upon a little reflection, must see that the definition is by no means so simple or explicit as could be desired. What has a line's being divided to do with the proof of its straightness? The great fault of all definers, from Dr. Johnson downwards, is, that they forget that definitions are wanted chiefly for the simple and unlearned.