Gengembre in 1783 endeavoured to unite phosphorus with the alkalies; in this he failed of success, but discovered the phosphuret of hydrogen, or the spontaneously inflammable gas now denominated phosphuretted hydrogen. (Journal de Physique, 1785.) In 1786 Mr. Kirwan published some experiments on phosphuretted hydrogen, (Philos. Trans.); he ascertained that water impregnated with this gas had the property of precipitating various metals from their solutions. The ingenious and indefatigable Pelletier has more merit than any other person in his investigations of the phosphurets. An important memoir of his on the manufacture of phosphorus in the large, is given in the Journal de Physique for 1785; in this he states that 4 or 5 lbs. sulphuric acid are commonly requisite for 6 lbs. calcined bones; and that from 18 lbs. calcined bones he obtained by the usual process, 12 oz. of phosphorus. In 1788 he read an essay on the phosphurets of gold, platina, silver, copper, iron, lead and tin. (An. de Chimie, 1--106). In 1790 he published an essay on the combinations of phosphorus with sulphur. (_Ibid._ 4--1). An additional memoir was published in 1792 on the same metallic phosphurets; and another on the phosphurets of mercury, zinc, bismuth, antimony, cobalt, nickel, manganese, arsenic and the other metals. M. Raymond in the An. de Chimie, 1791, recommends, instead of potash, moist hydrate of lime and phosphorus in order to obtain phosphuretted hydrogen with greater facility; and in the same Annals for 1800 he asserts that water absorbs a considerable portion of phosphuretted hydrogen, and becomes capable of precipitating metals from their solutions in acids, and of forming phosphurets, in this respect resembling sulphuretted hydrogen. Mr. Tennant discovered in 1791 that carbonic acid combined with the earths and alkalies is capable of decomposition by phosphorus, in a red heat; and Dr. Pearson, following up the discovery, found that pure or caustic lime may be united to phosphorus by heat so as to form phosphuret of lime; and that this dry compound when put into water is decomposed and gives out bubbles of phosphuretted hydrogen gas, which as usual explode spontaneously on reaching the surface of the water and coming into contact with the air. In 1810 I published the method of analysing phosphuretted hydrogen by Volta’s eudiometer; having found that this gas and oxygen may be mixed together in a narrow tube without explosion and afterwards exploded as other similar mixtures by an electric spark. Dr. Thomson published an essay on phosphuretted hydrogen in the Annals of Philosophy for August, 1816. He agrees with me very nearly as to the constitution and properties of this gas, as far as I have gone; but he has ascertained several additional properties of the gas, which I shall advert to in the sequel.