1802, 8vo. Electro-Chemical Researches on the Decomposition of the Earths; with Observations on the Metals obtained from the Alkaline Earths, and an Amalgam procured from Ammonia.--Lecture on a Plan for improving the Royal Institution, and making it permanent. 1810,8vo.-Elements of Chemical Philosophy. 1812, Svo.Elements of Agricultural Chemistry, in a Course of Lectures before the Board of Agriculture. 1813, 4to. and 8vo.Practical Hints on the Application of Wire Gauze to Lamps, for preventing Explosions in Coal Mines. 1816, 8vo. -Six Discourses delivered before the Royal Society, at their Anniversary Meetings, on the Award of the Royal and Copley Medals; preceded by an Address to the Society, delivered in 1800, on the Progress and Prospects of Science. 4to.

The following chronological series will show the number and value of the articles contributed by sir Humphry to the Philosophical Transactions :

Account of some Galvanic Combinations formed by the Arrangement of single Metallic Plates and Fluids, analogous to the new Galvanic Apparatus of M. Volta. 1801.-Account of some Experiments and Observations on the constituent Parts of certain astringent Vegetables, and on their Operation in Tanning. 1803.--An Account of some analytical Experiments on a Mineral Production from Devonshire, consisting principally of Alumine and Water. 1805. On a Method of analysing Stones, containing fixed Alkali, by means of the Boracic Acid. 1805.--The Bakerian Lecture on some Chemical Agencies of Electricity. 1807.--The Bakerian Lecture on some new Phenomena of Chemical Changes produced by Electricity, particularly the Decomposition of the fixed Alkalies, and the Exhibition of the new Substances which constitute their Basis, and on the general Nature of Alkaline Bodies. 1808.-The Bakerian Lecture; an Account of some new analytical Researches on the Nature of certain Bodies, particularly the Alkalies, Phosphorus, Sulphur, Carbonaceous Matter, and the Acids hitherto undecompounded; with some general Observations on Chemical Theory. 1809. -New Analytical Researches on the

Nature of certain Bodies; being an Appendix to the Bakerian Lecture for 1808. The Bakerian Lecture for 1809, on some new Electro-Chemical Researches, on various Objects, particu larly the Metallic Bodies from the Alkalies and the Earths, and on some Combinations of Hydrogen. 1810.-Researches on the xymuriatic Acid, its Nature and Combinations, and on the Elements of the Muriatic Acid; with some Experiments on Sulphur and Phosphorus, made in the Laboratory of the Royal Institution. 1810.- The Bakerian Lecture, on some of the Combinations of Oxymuriatic Gas and Oxygen, and on the Chemical Relations of these Principles to inflammable Bodies. 1811. Also another paper in the same volume in continuation of the subject.— On some Combinations of Phosphorus and Sulphur, and on some other Subjects of Chemical Inquiry. 1812.-Two papers on a new Detonating Compound. 1813. Some Experiments and Observations on the Substances produced in different Chemical Processes on Fluor Spar. 1813.-An Account of some new Experiments on the Fluoric Compounds; with some Observations on other Objects of Chemical Inquiry. 1814.-Some Experiments and Observations on a new Substance, which becomes a violetcoloured Gas by Heat. 1814.-Further Experiments and Observations on Iodine. 1814.-Some Experiments on the Combustion of the Diamond, and other carbonaceous Substances. 1814.- Some Experiments and Observations on the Colours used in Painting by the Ancients. 1815.-Some Experiments on a solid Compound of Iodine and Oxygen, and on its Chemical Agencies. 1815.— On the Action of Acids on the Salts usually called Hyperoxy muriates, and on the Gases produced from them. 1815. -On the Fire-damp of Coal-mines, and on Methods of Lighting the Mines so as to prevent Explosion; an Account of an İnvention for giving Light in explosive Mixtures of Fire-damp in Coal. mines, by consuming the Fire-damp; and further Experiments on the Combustion of explosive Mixtures confined by Wire Gauze; with some Observations on Flame. 1816.-Some Researches on Flame; and some new Experiments and Observations on the Combustion of Gaseous Mixtures; with an Account of a Method of preserving continued Light in Mixtures of inflammable Gases and

one of the candidates for the appointment of physician to that foundation. His principal opponent was Dr. Pemberton, who, either by superior interest, or by his more polished manners, obtained the situation. This second defeat in his professional career considerably lessened the ardour with which Dr. Wollaston had set out: he expressed his determination never again to write a prescription. Though almost every branch of science occupied him at different times, chemistry was that to which he seems to have been most ardently devoted; and it is by his investigations in this department of natural philosophy that he will enjoy his greatest share of lasting reputation.

The manner in which he was accustomed to pursue his inquiries was almost peculiar to himself. It was always on the smallest specimens of the substance which he wished to analyze that his experiments were made; and his labo-, ratory was, it is said, only in proportion to the magnitude of his materials. Dr. Thomson, in his "History of the Royal Society," when speaking of modern British chemistry, says, that "three distinct schools (if we may use the expression) have been established by three gentlemen," Dr. Wollaston, Mr. (the late sir Humphry) Davy, and Mr. Dalton. "Dr. Wollaston," he adds, "possesses an uncommon neatness of hand, and has invented a very ingenious method of determining the properties and constituents of very minute quantities of matter. This is attended with several great advantages: it requires but very little apparatus, and therefore the experiments may be performed in almost any situation: it saves a great deal of time and a great deal

of expense; while the numerous discoveries of Dr. Wollaston demonstrate the precision of which his method is susceptible."

Among the delicate instruments, which he was accustomed to make in a remarkably neat manner, was a sliding rule of chemical equivalents, which is exceedingly useful to the practical chemist. He also constructed a galvanic battery of such small dimensions, that it was contained in a thimble. By inserting platina wire in silver, and when at great heat drawing out both together, and afterwards separating them by dissolving away the silver with nitrous acid, he likewise produced some wire of platina of so diminutive a diameter as to be very much finer than any hair, and almost imperceptible to the naked eye.

Small, however, as was Dr. Wollaston's laboratory, and minute as were the means to which he had recourse in making his experiments, they proved exceedingly profitable to his purse. His discovery of the malleability of platinum it has been asserted, alone produced about 30,000l. He is also said to have derived great pecuniary advantages from several of his other, and even minor discoveries and inventions, which, being of a nature likely to be generally useful, were certain in a short time to produce a considerable return. It has been doubted by some whether this distinguished man, great as he was in science, and possessing many excellent qualities, would not have been greater, had his views been somewhat less directed to the acquisition of a fortune. But though he possessed the prudence which acquires wealth, he was free from the ironhearted parsimony which buries it. Having been applied to by a re

lation who was involved in unexpected difficulties, to procure him some government situation, Dr. Wollaston's reply, was, "I have lived to sixty without asking a single favour from men in office, and it is not, after that age, that I shall be induced to do so, even to serve a brother: if the inclosed can be of use to you in your present difficulties, pray accept it, for it is much at your service." The enclosed was a cheque for ten thousand pounds.

. Some curious anecdotes are told respecting the resolute manner in which Dr. Wollaston uniformly resisted the intrusion of either friend or stranger into his workshop. Among others, it is related, that a gentleman of his acquaintance, having been left by the servant to ramble from one room to another, till he should be ready to see him, penetrated into the laboratory. The doctor, on coming in, discovered the intrusion: but not suffering himself to express all he felt on the occasion, took his friend by the arm, and having led him to the most sacred spot in the room, said, "Mr. P., do you see that furnace?"-"I do."" Then make a profound bow to it, for as this is the first, it will also be the last time of your seeing it."

Dr. Wollaston was elected a Fellow of the Royal Society in 1793, and was elected Second Secretary Nov. 30th, 1806. His communications to the Philosophical Transactions commenced in 1797, and amount to the following numerous list :

In 1797, "On the Gout, and Urinary Concretions;" in 1800,"On Double Images caused by Atmospherical Refraction;" in 1801, "Experiments on the Chemical Production and Agency of Electricity;" in 1802, "A Method of

examining Refractive and Dispersive Powers by Prismatic Reflection," and a Iceland Crystal;" in 1803, the Bakerian paper "On the Oblique Refraction of lecture, consisting of "Observations on the Quantity of Horizontal Refraction; with a Method of measuring the Dip at Sea;" in 1804, a paper "On a new Metal found in crude Plate;" in 1805 another, "On the discovery of Palladium, with Observations on other Substances

found with Platina;" in 1806, the Ba

kerian lecture, "On the force of Percussion;" in 1807, an "Essay on Fairyrings;" in 1808, three "On Platina and Native Palladium from Brazil,” “On the Identity of Columbium and Tantalum," and a "Description of a Reflective Goniometer;" in 1810, the Croonian lecture, "On Muscular Action, Sea Sickness, and the salutary Effects of Exercise on Gestation ;" and an Essay "On Cystic Oxide, a new Species of Non-existence of Sugar in the Blood of Urinary Calculus ;" in 1811, "On the Persons labouring under Diabetes Mellitus;" in 1812, two papers "On the Primitive Crystals of Carbonate of Lime, Bitter Spar, and Iron Spar," and Microscope;" in 1813, the Bakerian "On a Periscopic Camera Obscura and lecture, On the Elementary Particles of certain Crystals;" the explanation of "A Method of drawing extremely fine Wires," and "A Description of a Single-lens Microscope;" in 1820, articles

"On the Methods of Cutting Rock Crystal for Micrometers," and "On Sounds inaudible by certain Ears."

Dr. Wollaston communicated, in 1815, Description of an Elementary Galvanic to Thomson's Annals of Philosophy, "A Battery;" and to the Philosophical Magazine, in 1816, "Observations and Experiments on the Mass of Native Iron found in Brazil."

for

Within the last session only, in the midst of which his decease occurred, five essays by Dr. Wollaston were read before the Royal Society. The first was the Bakerian lecture, "On a Method of rendering Platina Malleable;" which, on their last anniversary, November 30th, 1828, the Royal Society awarded to the inventor one of the royal medals. The subjects of the remainder were "On a Microscopic Double ;". "On a Differential Barometer;" "On a Method of comparing the Light of the Sun with that of the Fixed Stars ;" and "On the Water of the Mediterranean."

The following honourable eulogy on Dr. Wollaston was pronounced by the President of the Royal Society, on the anniversary meeting upon the 1st of December, 1828. Having announced that the council of the Royal Society had awarded one of the royal medals of the year to Mr. Encke, "for his researches and calculations respecting the heavenly body usually distinguished by his name," Mr. Gilbert thus proceeded :

"The other royal medal has been awarded by your council for a communication made under circumstances the most interesting and most afflicting. An individual, of whom not the Society alone, but all England, is justly proud, whose merits have been appreciated and distinguished by each of the eminently scientific establishments of Europe, has recently been assailed by a malady, one of the most severe to which human nature is exposed. But the energies of his mind soaring beyond bodily infirmities, he has employed them in a manner (I will presume to say) most acceptable to the Divinity, because most usefully to mankind, by imparting, through the medium of this society, further stores of knowledge to the world, which has been so frequently before illuminated by the splendour of his genius. Ón the first day of our meeting a paper from Dr. Wollaston was read, descriptive of the processes and manipulations by which he has been enabled to supply all men of science with the most important among the recently discovered metals. Platinum, possessed of various qualities useful in an eminent degree to chemists, even on a large scale, withheld them all by resisting fusion in the most intense heat of our wind furnaces. Alloy

ed, indeed, with arsenic, it became susceptible of receiving ornamental forms; but a continued heat expelled the volatile metal, and left the other in a state wholly unfit for use. Dr. Wollaston, instead of alloying, purified the platinum from every admixture by solution, consolidated its precipitate by pressure, by heating, and by percussion, so as to effect a complete welding of the mass, thus made capable of being rolled into leaf, or drawn into wire of a tenacity intermediate between those of iron and gold. To these scientific and beautiful contrivances we owe the use of a material, not only of high importance to refined chemistry, but now actually employed in the largest manufactories for distilling an article of commerce so abundant and so cheap as sulphuric acid. And above all, we owe to them the material which, in the skilful hands of some members of this society, has mainly contributed to their producing a new species of glass, which promises to form an epoch in the history of optics. Your council have, therefore, deemed themselves bound to express their strong approbation of this interesting memoir (independently of all extraneous circumstances,) by awarding a royal medal to its author. And they anticipate with confidence a general approbation, in both these instances, of what they have done."

Of the Geological Society, Dr. Wollaston became a member in 1812: he was frequently elected on the council, and was for some time one of the vice-presidents. He made no contributions to the publications of that learned body; but he was well acquainted with the scope of their inquiries, and always attended to the geological