change of the Brahman with his pot of rice into the milkmaid with her pot of milk took place in the thirteenth century, and was that adopted by La Fontaine. He then described more minutely the ramifications of this cluster of Indian fables in their progress from East to West, pointing out some other channels through which such tales as the stories of Sindbad reached the literary market of Europe. In conclusion, he showed that even a Father of the Church had exercised an important influence in importing Eastern fables into Europe. Joannes Damascenus lived at the court of the same Chalif Almansur for whom Abdallah-ibn-Almokaffa had translated the fables from Pehlevi into Arabic. In a religious novel, called 'Barlaam and Josaphat,' Joannes not only introduced a number of Eastern fables, but actually took his principal hero, Josaphat, from the LalitaVistara,' the life of the Buddha, or "Enlightened," a portion of the sacred canon of the Buddhists. That the story of Barlaam is, in its most striking points, a mere repetition of the story of the Buddha the Professor proved by quoting many names; and, finally, he drew attention to the fact that Josaphat, the hero of the story of Joannes Damascenus, had been raised to the rank of a saint both in the Eastern and Western Churches. "What follows, then?" the Professor asked. "It follows that Buddha has become a saint in the Romish Church; it follows that, though under a different name, the sage of Kapilavastu, the founder of a religion which, in the purity of its morals, is nearer to Christianity than any other religion, and counts even now, after an existence of 2400 years, 455,000,000 of believers, has received the highest honours which the Christian Church can bestow. And whatever we may think of the sanctity of saints, let those who doubt the right of Buddha to a place among the saints read the story of his life, as told in the Buddhist canon. If he lived the life which is there described, few saints have a better claim to that title than Buddha; and no one, either in the Greek or in the Roman Church, need be ashamed of having paid to his memory the honour which was intended for St. Josaphat, the Prince, he hermit, and the saint." [M. M.] GENERAL MONTHLY MEETING, Monday, June 6, 1870. SIR HENRY HOLLAND, Bart. M.D. D.C.L. F.R.S. President, Miss Conway Griffiths. Hugh Martin Macpherson, Esq. F.R.C.S. Henry Sutherland, Esq. M.B. were elected Members of the Royal Institution. 66 The special thanks of the Members were returned for the following Donations to the Fund for the Promotion of Experimental Researches":— T. Williams Helps, Esq. (5th Donation) £10 25 Sir Henry Holland, Bart. M.D. (12th Annual Donation) 40 The PRESENTS received since the last Meeting were laid on the table, and the thanks of the Members returned for the same, viz. :— FROM The Count of Paris and the Duke of Chartres-Campagnes de l'Armée d'Afrique 1835-39, par le Duc d'Orléans, publié par ses Fils. 8vo. Paris. 1870. Anonymous-La Légitimité en Espagne: par H. de Lazeu. (K 97) 8vo. 1870. Asiatic Society of Bengal-Journal, No. 158. 8vo. Proceedings, 1870, No. 3. 8vo. British Architects, Royal Institute of-Sessional Papers, 1869-70, No. 9. 4to. Chemical Society--Journal for May, 1870. 8vo. Editors-Academy for May, 1870. 4to. Artizan for May, 1870. 4to. Athenæum for May, 1870. 4to. Chemical News for May, 1870. 4to. Engineer for May, 1870. fol. Horological Journal for May, 1870. 8vo. Journal of Gas-Lighting for May, 1870. 4to. Mechanics' Magazine for May, 1870. 8vo. Nature for May, 1870. 4to. Pharmaceutical Journal for May, 1870. 8vo. Photographic News for May, 1870. 4to. Revue des Cours Scientifiques et Littéraires. May, 1870. 4to. Jablonowski'schen Society, Leipsic-Preisschriften, XV. With Plates. 4to. 1870. Meteorological Society-Proceedings, No. 49. 8vo. 1870. North of England Institute of Mining Engineers-Transactions. Vols. XVII. XVIII. 8vo. 1867-9. Photographic Society-Journal. No. 217. 8vo. 1870. Prussian Academy, Royal-Monatsberichte, März, April, 1870. 1870. 8vo. Royal Irish Academy-Transactions: Science, Parts 9-15; Polite Literature, Part 4; Antiquities, Part 8. 4to. 1869-70. Royal Society of London-Proceedings, No. 119. 8vo. 1870. Samuel, Messrs.-Wool and Woollen Manufactures of Great Britain. 8vo. 1859. Symons, G. J. Esq. (the Author)-Symons' Monthly Meteorological Magazine, May, 1870. 8vo. Saxon Society of Sciences, Royal, Leipsic-Abhandlungen. 3 Parts. 4to. 1869. Berichte: 1867. Nos. 3, 4. 1868. 1869. No. 1. 8vo. T. Twining, Esq. M.R.I. (the Author)-Science for the People; a Memorandum. 8vo. 1870. United Service Institution, Royal - Journal, No. 57. 8vo. 1870. Van der Menbrugghe, C. (the Author)-Sur la Viscosité superficielle des Lames de la Solution de Saponine. 8vo. 1870. Zoological Society-Transactions, Vol. VII. Parts 1, 2. 4to. 1870. WEEKLY EVENING MEETING, Friday, June 10, 1870. SIR H. HOLLAND, Bt. M.D. D.C.L. F.R.S. President, in the Chair. WILLIAM ODLING, M.B. F.R.S. FULLERIAN PROFESSOR OF CHEMISTRY, ROYAL INSTITUTION, On the Ammonia Compounds of Platinum. FOR nearly a century past ammonia gas, discovered by Priestley in 1774, has been a subject of extreme interest to chemists. This ammonia gas, H,N, is especially characterized by its property of uniting directly with hydrochloric acid gas, HCl, to form a solid deposit of sal-ammoniac, or hydrochloride of ammonia, H,N. HCI. In several important particulars, sal-ammoniac presents a remarkable similarity of behaviour to chloride of potassium; and, by linking together the hydrogen of its acid with its ammonia so as to form the grouping H,N. H or H,N, it may be regarded as the chloride of a composite metal ammonium, just as potassium chloride is the chloride of the simple metal potassium; thus:- Ordinarily, when potassium chloride is subjected to the action of a weak current, no potassium, but only potash, makes its appearance at the negative pole; but if the negative pole be constituted of a drop of mercury, the electrolytically-liberated potassium remains dissolved in the mercury as potassium-amalgam K,Hg,. Similarly, when solution of sal-ammoniac is subjected to electrolysis, the negative pole being constituted of mercury, there is produced a bulky amalgam of ammonium (H,N.H),Hg,; which, however, when no longer under the influence of the current, speedily breaks up into ammonia, hydrogen, and mercury. Ammonium-amalgam may further be produced on a large scale by the action of potassium-amalgam or sodium-amalgam on sal-ammoniac solution, thus:— * KCl + (H,N.H), Hg, x (H,N.H)CI + K, Hg, = Another characteristic property of ammonia gas is its extreme solubility in water. By its dissolution it furnishes a liquid having many of the properties of aqueous potash, as, for example, the properties of affecting test-paper, of neutralizing acids, and of precipitating metallic salts. And just as sal-ammoniac may be regarded as a chloride of ammonium, analogous to chloride of potassium, so may aqueous ammonia be regarded as a hydrate of ammonium analogous to hydrate of potassium, thus: (H,N.H)HỌ KHO But whereas chloride of ammonium, analogous to chloride of potassium, constitutes a definite body,-hydrate of ammonium, analogous to hydrate of potassium, has an inferential existence only. It is inferred to exist in solution from the reactions of the solution; but, under all attempts at extraction, it breaks up into ammonia gas and water, thus: (H,N.H)HO or H2N. H2O = H2N + H2O But by far the most interesting circumstance with regard to ammonia is its property, so remarkably developed by Hofmann, of serving as a type from which compounds of the most varied character are derivable by substitution. Just, for example, as the hydrocarbon residue, or radical, ethyl CH,, can replace the hydrogen of hydrochloric acid to form ethylic chloride CH,. Cl, so can it also replace the hydrogen of ammonia to form ethylamine C,H,. H.N. This ethylamine constitutes a very volatile liquid, vaporizing considerably even at ordinary temperatures. Its vapour closely resembles ammonia gas, but is distinguishable therefrom by its ready inflammability. Like ammonia, ethylamine combines directly with hydrochloric acid to form ethylamine sal-ammoniac, or hydrochloride of ethylamine CH, H2N. HCl. Like ammonia, also, ethylamine is extremely soluble in water; and its solution, like that of ammonia, behaves in many respects as a definite hydrate CH, H2N.H2O, not obtainable, however, in the isolated state, but, like hydrate of ammonia, known only in the state of solution. There exist, moreover, derivatives of ammonia in which a portion of its hydrogen is replaced, not by a monad, but by a diad residue or radical. Just, for example, as diad ethylene, CH, replaces the hydrogen of two units of hydrochloric acid to form ethylenic chloride, CH.. Cl2, so can it also replace, in part, the hydrogen of two units of ammonia to form ethylenamine, C.H.(HN), or (C,H,)"H,N2. This double ammonia unites with two units of hydrochloric acid to form the definite hydrochloride, C,H,(H,N),.2HCl, and with two units of water to form the equally definite, stable, isolable, volatile, crystallizable hydrate C2H,(H,N),. 2H2O. The hydrochloride and non-isolable hydrate of ethylamine being compared with the chloride and hydrate of the monad alkali-metal potassium, the hydrochloride and isolable hydrate of ethylenamine are similarly comparable with the chloride and hydrate of the diad alkali-metal barium, thus: K'CI {C2H,(H,N)H}'Cl K'HO { C2H ̧(H2N)H}'HO Ba"Cla {C2H,(H,N), } "Cl2 And hydrate of ethylenamine agrees with hydrate of barium, as well in being a powerfully alkaline base, as in being de-hydrateable, not by the action of heat, but by indirect methods only. Through the further researches of Hofmann, chemists are acquainted with ammonias and di-ammonias, in which, not only onethird, but two-thirds and three-thirds of the hydrogen are replaced by monad ethyl and diad ethylene respectively. With regard to these compounds, both in their properties and in the nature of the VOL. VI. (No 53.) N hydrochlorides and hydrates which they furnish, di- and tri-ethylamine correspond very closely to ethylamine-di- and tri-ethylenamine very closely to ethylenamine. Although, in this way, the principal developments and ultimate establishment of the idea of ammonia as a type have resulted from investigations in organic chemistry, the idea itself appears to have originated in the first instance from investigations made in mineral chemistry; and especially from the investigation of compounds formed by the reaction of certain metallic salts and ammonia. Graham, indeed, had early represented certain compounds of metallic chlorides with ammonia as being metallicized sal-ammoniacs; but the notion of ammonia as a trihydric type, susceptible of three successive degrees of substitution, was first enunciated by Laurent, and was employed by that most original chemist to explain, among other matters, the constitution of different ammoniated compounds of platinum, discovered by Magnus, Gros, and Reiset successively. These compounds he represented as being salts of derived ammonias, in which different proportions of the hydrogen of ammonia were replaced by platinum. Platinum is a moderately hard, pewter-coloured metal, possessed of many singular properties. It was first recognized as a distinct metal by Wood, an assayer of Jamaica, in 1741. The mode of working it was discovered and practised by Wollaston early in the present century, and described by him in the Philosophical Transactions' for 1829. Platinum is especially characterized by its high specific gravity; by its low conductivity, dilateability, and specific heat; by its high ductility and tenacity; by its facile divisibility and reducibility; by its curious absorptivity of certain gases, more especially hydrogen; by its difficult attackability by chemical agents; and by its infusibility at the highest furnace heats. And by each of these several properties, except perhaps its high specific gravity, is it suited to some special application in the arts. Chemically, platinum is characterized by its high atomic weight, 197; and by its formation of two well-defined chlorides,-a perchloride, also known as platinic chloride, expressed by the formula Pt"""Cl, and a protochloride, also known as platinous chloride, expressed by the formula Pt"Cl. Platinic chloride occurs in crystalline, dark orange masses, freely soluble in water. Platinous chloride forms an olivebrown amorphous powder, quite insoluble in water, but dissolving in hydrochloric acid to form an ochre-coloured liquid. In 1828, the late Professor Magnus, by supersaturating this liquid with ammonia, obtained a remarkable compound, containing the elements of platinous chloride and ammonia, and presenting itself as a dull green, usually crystalline, precipitate. This notable green precipitate has formed the subject of |