In 1824 Faraday again brought to the Royal Society a chemical discovery of first importance. The paper was on some new compounds of carbon and hydrogen, and on certain other products obtained during decomposition of oil by heat. From condensed oil-gas, so obtained, Faraday succeeded in separating the liquid known as benzin or benzol, or, as he named it at the time, bicarburet of hydrogen. It has since its discovery formed the basis of several great chemical industries, and is manufactured in vast quantities. Prior to the reading of this paper he had, as we have already related, been elected a Fellow of the Royal Society, an honour to which he had for some years aspired, and which stood alone in his regard above the scientific honours of later years. In this year he tried, amongst his unsuccessful experiments, two of singular interest. One was an attempt to find whether two crystals (such as nitre) exercised upon one another any polar attractions like those of two lodestones. He suspended them by fibres of cocoon silk, and, finding this material not delicate enough, by spider-lines. The other was an attempt to discover magneto-electricity. For various reasons he concluded that the approximation of the pole of a powerful magnet to a conductor carrying a current would have the effect of diminishing the amount of that current. He placed magnets within a copper wire helix, and observed with a galvanometer whether the current sent through the circuit of the helix by a given battery was less when the magnet was absent. The result was negative. [Sidenote: RESEARCH ON OPTICAL GLASS.] In this year also began the laborious researches on optical glass, which though in themselves leading to no immediate success of commercial value, nevertheless furnished Faraday with the material essential at the time for the making of the most momentous of all his discoveries. A committee had been appointed by the President and Council of the Royal Society for the improvement of glass for optical purposes, and Faraday was amongst those chosen to act upon it. In 1825 the Royal Society Committee delegated the investigation of optical glass to a sub-committee of three, Herschel (afterwards Sir John), Dollond (the optician), and Faraday. The chemical part, including the experimental manufacture, was entrusted to Faraday. Dollond was to work the glass and test its qualities from the instrument maker’s point of view, whilst Herschel was to examine its refraction, dispersion, and other physical properties. This sub-committee worked for nearly five years, though by the removal of Herschel from England its number was reduced to two. In 1827 the work became more arduous. Faraday thus writes:--