might teach the application of science to the advancement of the arts of life, advance the taste and science of the country, and improve the means of industry and domestic comfort among the poor. These benevolent designs were to be promoted by committees for the purpose, having for their object the advancement, by scientific investigation, of the arts of life, on which the subsistence of all, and the comfort of the great majority of mankind, absolutely depend. At this early period of its history,' says Dr. Paris, the Royal Institution presented a scene of the most animated bustle and exhilarating activity. It was "like a busy ant-hill in a calm sunshine."

At the commencement of 1805, Davy enriched the cabinets of the Institution by a present of minerals, which were reported to be of the value of 100 guineas; and he was soon after, in addition to his professorship, appointed director of the laboratory; by which appointment, his annual income from the Institution was raised to four hundred guineas. At this period he delivered a series of lectures on Geology, and produced his paper, published in the Philosophical Transactions, Analytical Experiments on a Mineral Production from Derbyshire (Wavellite), consisting principally of Alumina and Water;' and soon after he communicated to the same body a paper On the Method of analyzing Stones containing a fixed Alkali, by means of the Boracic Acid,' which is said to have much advanced the art of mineral analysis. On the death of Dr. Gray, Davy was elected secretary of the Royal Society, at an extraordinary meeting on the 22d Jan. 1807, being at the same time elected a member of the council. In Chapter VI. of his work, Dr. Paris enters upon that brilliant period in the life of Davy, at which he effected those grand discoveries in science, embracing the development of the laws of voltaic electricity, which will transmit his name to posterity;' prefixed we have a brief view of the history of galvanism, or voltaic electricity, divided into six grand epochs. Davy, in his Bakerian lecture of 1806, remarks-

That the true origin of all that has been done in this department of philosophy was the accidental discovery, by Nicholson and Carlisle, of the decomposition of water by the pile of Volta, in April, 1800, which was immediately followed by that of the decomposition of certain metallic solutions, and by the observation of the separation of an alkali on the negative plates of the apparatus. Mr. Cruikshank, in pursuing these experiments, obtained many new and important results, such as the decomposition of the muriates of magnesia, soda, and ammonia; and also observed the fact that the alkaline matter always appeared at the negative, and acid matter at the positive pole.'

In September, 1800, Davy published his first paper on the subject of galvanic electricity, in Nicholson's Journal, which was followed by six others, in which he so far extended the original experiment of Nicholson and Carlisle, as to show that oxygen and hydrogen might be evolved from separate portions of water, though vegetable and even animal substances intervened; and conceiving that all decompositions might be polar, he electrised different compounds at the different extremities, and found that sulphur and metallic bodies appeared at the negative pole, and oxygen and azote at the positive pole, though the bodies furnishing them were separated from each other. Here was the dawn of the electro

chemical theory.. The Bakerian Lecture, read before the Royal Society in November, 1806, unfolded the mysteries of voltaic action; and, as far as theory goes, may be almost said to have perfected our knowledge of the chemical agencies of the pile.'

Of this celebrated paper, Dr. Paris has given an analysis, to which we must refer the reader; it embraces the discovery of the sources of the acid and alkaline matter eliminated from water by voltaic action-the nature of electrical decomposition and transferthe relations between the electrical energies of bodies and the chemical affinities-a general development of the electro-chemical laws, and their application. He thus concludes what Dr. Paris justly styles one of the most masterly and powerful productions of scientific genius

Natural electricity has hitherto been little investigated, except in the case of its evident and powerful concentration in the atmosphere. Its slow and silent operations, in every part of the surface, will probably be found more immediately and importantly connected with the order and economy of nature; and investigations on this subject can hardly fail to enlighten our philosophical systems of the earth, and may possibly place new powers within our reach.

Dr. Paris asserts that accident, which so mainly contributed to former discoveries in electricity, had no share in conducting Davy to the truth in this instance, but that he unfolded, with philosophic caution and unwearied perseverance, all the particular phenomena and details of his subject, and with the comprehensive grasp of genius caught the plan of the whole.

Buonaparte having founded a prize of three thousand francs (about £120), to be adjudged by the Institute, for the best experiment which should be made in each year on the galvanic fluid, and another of sixty thousand francs to the person who, by his experiments and discoveries, should advance the knowledge of electricity and galvanism as much as Franklin and Volta did-the first prize was awarded to Davy, about twelve months after the publication of his first Bakerian Lecture, for his discoveries announced in the Philosophical Transactions of 1807. When the bitter animosity which France and England mutually entertained towards each other at this period is recollected, the award was not more honourable to him who received the prize than to those who gave it.

In November, 1807, his second Bakerian Lecture was read, in which he announces the discovery of the metallic bases of the fixed alkalies

'a discovery immediately arising from the application of voltaic electricity, directed in accordance with the electro-chemical laws he had developed. Thus having, in the first instance, ascended from particular phenomena to general principles, he now descended from those principles to the discovery of new phenomena; a method of investigation by which he may be said to have applied to his inductions the severest tests of truth, and to have produced a chain of evidence without having a single link deficient. Since the account given by Newton of his first discoveries in optics, it may be questioned whether so happy and successful an instance of philosophical induction has occurred."

Dr. Paris, as before, gives a detailed account of the contents of this

lecture, which we regret we have not space to copy. In the lecture, Davy observes, that an historical detail of the progress of the investigation, of all the difficulties that occurred, of the manner in which they were overcome, and of all the manipulations employed, would far exceed his limits,' upon which Dr. Paris observes that, to the chemist, every circumstance connected with a subject of commanding importance is pregnant with interest;' and having, by permission of the managers of the Royal Institution, obtained leave to examine and make extracts from the Laboratory Register, he obtained the following interesting clue to the intellectual operations by which his mind ultimately arrived at the grand conclusion.' With these interesting MS. volumes we hope to make the reader acquainted in a future page of this Journal-in the meantime we shall follow Dr. Paris :

It appears from this register, that Davy commenced his inquiries into the composition of potash on the 16th, and obtained his great result on the 19th of October, 1807. His first experiments, however, evidently did not suggest the truth; he does not appear to have suspected the nature of the alkaline base until his last experiment, when the truth flashed upon him in the full blaze of discovery. His first note, dated the 16th, leads us to infer that he acted on a solid piece of potash, under the surface of alcohol, and several other liquids in which the alkali was not soluble; and that he obtained gaseous matter which he called at the moment "alkaligen gas," and which he appears to have examined most closely, without arriving at any conclusion as to its nature. On the following day, he, for the first time, would seem to have developed potassium by electric action on potash, under oil of turpentine, for the note records the fact of "the globules giving out gas by water, which gas burnt in contact with air;" and then follows a query-"Does it" (the matter of the globules) "not form gaseous compounds with ether, alcohol, and the oils ?" Here then he evidently imagined, that the matter of the globules, which he had never obtained from potash, except when acted upon under oil of turpentine, had formed gaseous compounds with the ether, alcohol, and oils, in his previous experiments, and given origin to that which he had termed "alkaligen gas." He then leaves the consideration of this gas, and attacks the unknown globules, which probably did not present any metallic appearance under the circumstances he saw them, for they must have been as minute as grains of sand. I rather think that he commenced his examination by introducing a globule of mercury, and uniting it with a globule of the unknown substance, for his note says-" Action of the substance on mercury, forms with it a solid amalgam, which soon loses its alkaligen in the air." And from the note which succeeds, he evidently considered this alkaligen (potassium) volatile, as he says, soon flies off on exposure to the air."

"it

October 19.-It is probable that, in consequence of the property which the unknown substance displayed of amalgamating with mercury, he devised his experiment of the 19th. He took a small glass tube, about the size and shape of a thimble, into which he fused a platinum wire, and passed it through the closed end. He then put a piece of pure potash into this tube, and fused it into a mass about the wire, so as entirely to defend it from the mercury afterwards to be used. When cold, the potash was solid, but containing moisture enough to give it a conducting power; he then filled the rest of the tube with mercury, and inverted it over the trough: the apparatus being thus arranged, he made the wire and the mercury alternately positive and negative;-and now, conceiving that I

have sufficiently explained his brief notes, the reader shall receive the result in his own words: on the same day he decomposed soda with somewhat different phenomena.'

Dr. Paris has given a fac-simile of the minute in Davy's handwriting of his successful experiment of October the 19th. It is highly interesting and characteristic, but should have been accompanied by the substance of it in print, for it is not every one who will be able to decipher it. It runs thus:

Oct. 19.-When potash was introduced into a tube having a platina wire attached to it, and fixed into the tube so as to be a conductor, i. e., so as to contain just water enough, though solid, and inserted over mercury, when the platina was made negative, no gas was formed, and the mercury became oxydated, and a small quantity of the alkaligen was produced round the platina wire, as was evident from its quick inflammation by the action of water. When the mercury was made the negative, gas was developed in great quantities from the positive wire, and none from the negative mercury, and this gas proved to be pure oXYGENE.— CAPITAL EXPERIMENT, proving the decomposition of POTASH.'

Those who knew Davy will best conceive the enthusiasm with which this hasty record of his success was dashed off, and will recognise supna in his 'capital experiment!'

(To be continued.)

I. Planta Asiatica Rariores; or Descriptions and Figures of a select number of unpublished East India Plants. By N. Wallich, M.D. Vol. I. folio. London, 1830. Treuttell and Co. II. A numerical List of dried Specimens of Plants in the East India Company's Museum, collected under the superintendence of N. Wallich, of the Company's Botanic Garden at Calcutta. Folio, pages 1-93, Nos. 1-3285; still publishing. (For private distribution only.)

F we were to select one country in preference to another, as

modern science, India and its vegetation should be our themeIndia, which in its vast extent comprehends the climate of the equator and of the Pole, stretching from the classical mountains of Emodus on the north, to the ancient Taprobane, and the sultry islands of the Indian Archipelago on the south; and from the rose gardens of Amedabad, and the holy fountains and luxurious palaces of Cachmere on the west, to the frontiers of the celestial empire and the burning shores of Arracan, Pegu, and Martaban on the east; embracing regions of eternal snow among the craggy summits of the Himalaya and Nilgherry; parched plains, where the sun glares with his fiercest rays in Hindostan; and including all those gradations and diversity of climate which are the usual characteristics of an entire quarter of the globe, rather than of a country subject to the control of a single power, and distinguished by a single name ;—a vegetation which seems, at first sight, to be in direct contradiction to

any known law that regulates the embellishment of the face of nature; where the orange and the lime, the shaddock, the pineapple and the banana, grow almost side by side with the oak, the bramble, and the chesnut; which, in one district, consists of roses, elms, currants, raspberries, and wild flowers most similar to those of Europe; and in another, is so entirely tropical, that the trees are mangosteens and mangoes, and their inhabitants the parasitical loranthus, or the fantastic orchis, while the woods are of teak and sissoo, choked up by huge lianes; in which the sensible properties are so elaborated, that the very nettles become deadly, forest trees produce blindness, by mere contact with their juices, the poisons are of unheard-of virulence, and yet every sense is delighted by the fragrance of flowers of the most splendid colours, or by the rich flavour of the most luscious fruits.

The botany of this remarkable country has not failed to excite attention from the earliest periods. To say nothing of the Arabians, who first introduced ginger from Calicut to Spain-who described the pepper plant that climbs upon other trees, hiding its fruit beneath its leaves, lest the former be scorched up-who brought the sugarcane from the banks of the Ganges; discovered the true camphor tree of Sumatra; distinguished the rhubarb that grows on the confines of China from the rheum of the Greeks; and made known the tamarind, the cotton plant, the tea tree, the nutmeg, and the cinnamon; and to pass by the now-forgotten names of Garcias ab Orta, Acosta, Linschoten, and Jacob Bont, there are two works that especially claim our attention.

In the middle of the seventeenth century, a Dutch Viceroy of Malabar, named Henry van Rheede tot Drakenstein, collected by means of Brahmins, missionaries, and others, a great store of drawings and descriptions of the more important plants of his government, which were subsequently published between the years 1676 and 1703, in twelve volumes, folio. Like the Flora Batava,' now publishing at the expense of the King of the Netherlands, the skill of the subordinate agents was by no means commensurate with the liberality of their princely employers, whose treasures were unfortunately lavished upon a work that was far from answering to the charges that were incurred in its publication. About seven hundred indifferent figures, accompanied by miserable descriptions, were the whole result of Van Rheede's patronage.

About the same time, the Flora of Insular India was investigated by George Everhard Rumf, a Dutch merchant and governor of Amboyna, whose collections were published in seven volumes folio, by John Burmann, between 1741 and 1751. Unlike Van Rheede, Rumf appears to have been a skilful botanist for his time, as well as a munificent patron; and hence both the figures and descriptions of the Herbarium Amboinense,' as his work is called, are of a character far superior to that of his predecessor. Like all drawings of natural history of the day, the figures are inaccurate in their details, but they are far from bad general representations; the