In this lecture Faraday gives the details of twenty experiments. On April 8 Professor Davy lectured on Simple Inflammable Bodies. ‘Their number, excepting the metals, is six, which unite with oxygen and chlorine, the subjects of the two last lectures.’ He showed a jet of oxygen burning in hydrogen, and said, ‘In the burning of tallow, wax, oil, and wood it is the hydrogen of their bodies that causes the flame; though in most cases it is also combined with carbon, yet it is the hydrogen that produces the flame.... ‘I have here a bladder filled with nitrous oxide gas; I will breathe it once or twice, but not so far as to incapacitate me from continuing the lecture. It produces a very pleasing sensation (far superior to the most exquisite liquors, such as champagne), and I have no doubt that if I were to continue it a few minutes longer I should make a very interesting exhibition to the company; but I would rather be excused.... ‘If we suppose that the diamond is pure carbon, and is therefore the same as charcoal, we have a very strong presumptive reason to suppose that all matter is alike in all substances. If substances so opposite and so different as charcoal and diamond are in reality the same kind of matter, then the difference in other bodies is no proof that they also are not of the same kind of matter; and this would lead us to suppose that there is but one matter in nature, and that the difference in different bodies is owing to variety in the distance of the particles, to shape, and to size.... ‘In conclusion several of these six simple combustibles I suspect to be compounds, and perhaps their nature may shortly be discovered.... ‘What gives a strong colour to the idea of the compound nature of nitrogen is the quantity of it that can be obtained from animal bodies, whereas they imbibe none, they combine with none. ‘Sulphur and phosphorus both appear to be compound bodies when they are subjected to the power of a voltaic battery. A great quantity of hydrogen gas is evolved, so that it appears hydrogen is one of their constituent parts.... ‘Whether these bodies are compound or not, they are objects of new research; they present new fields for the great, the industrious, the scientific, and the penetrating mind. Our horizon extends the higher we rise. The result of future inquiries will probably lay a foundation on which future ages and future generations may erect an edifice that will reach from earth to heaven.’ In this lecture Faraday noted twenty-two experiments. The next day, April 9, Davy was knighted by the Prince Regent. On April 10 Sir Humphry Davy gave his last lecture at the Royal Institution; it was on the Metals. ‘All the volatile metals burn with flame, and all those that are not volatile with sparks.... ‘These, with the metals of the alkalies and the alkaline earths which I have had the good fortune to discover, make up the number to about forty.’