Once he had been shown the door into the Royal Institution, everything that happened subsequently to Faraday came as a result of his own efforts, determination and self-possession. The letters to Abbott amply demonstrate the calibre of the intellect that Riebau had taken on as an apprentice, and that Sir Humphry Davy had now engaged. Within three months of starting as Davy’s assistant, Faraday had become by observation as much an expert on lectures and lecturing techniques as anybody in London. There are four long letters to Abbott which examine in detail the finer and the coarser points of the art of lecturing, and consider too a lecturer’s needs, his equipment, illustrations, the design of the lecture theatre, its ventilation, seating, sight-lines, and entrance and exit arrangements. The most extraordinary thing about this is that Faraday, who had done no public lecturing himself, and who had not experienced any university lecturing, with its syllabuses, regular classes and so on, should so rapidly find the key to clarity in an art that was so widely abused. His notes, since they were first published in 1870,56 have for more than a hundred years been widely and influentially used as benchmarks to guide aspiring lecturers. The only other person in Faraday’s ken who had come to lecturing afresh was Sir Humphry Davy himself in his professional journey from Penzance and Bristol to London. Between them they comprised the new wave of lecturing techniques, and re-invented the art.
Sir Humphry Davy threw Faraday in at the deep end. A month after he had begun at the Royal Institution, Faraday was working with Davy on the same nitrogen trichloride that had blown Dulong’s finger off, and sent glass into Davy’s eye. Faraday coolly told Abbott, ‘I have been engaged this afternoon in assisting Sr H in his experiments on it during which we had two or three unexpected explosions.’57
We know practically all there is to know about how to make nitrogen trichloride from Faraday’s letters to Abbott. The new explosive had great military potential, and, from the post-Cold War perspective of two hundred years later, it is revealing how unconcerned Davy, a man of the establishment and deeply anti-French, was about the security of information about the explosive.
Davy may not have given his assistant much warning about what might happen when the greasy, butter-like compound, which smelt curiously of almonds, was put into a basin of water, and then phosphorus was added to it. They concocted the compound itself the same day by making up solutions of ammonium nitrate and ammonium chloride, and then, using a scrupulously clean air jar, inverting over them some ‘fresh made pure clean’ chlorine gas. There is a note of triumph in the expression of that recipe – Davy was inordinately proud of chlorine. There must be no trace of oil, grease or any other impurities anywhere in the equipment, and it was Faraday’s job to see that everything was spotless. By now Davy was fully confident of his assistant’s care and dexterity in handling fragile laboratory equipment, his attention to detail and his physical bravery. A month after taking Faraday on Davy was prepared to trust his young assistant to work side by side at the bench with him on murderous substances.
Davy and Faraday began by keeping the ammonium solutions as cold as possible by surrounding the basins with ice, but soon they relaxed that operation as they found it slowed the process down. When the chlorine came into contact with the solution, the liquid began to rise dramatically up the jar, and drops of yellow oil rose and then gently dropped down into the liquid to lie as an oily layer at the bottom. They found slightly different rates of absorption between the nitrate and the chloride, but the compound that lurked at the bottom of the retort was more or less the same in both versions of the experiment.
Having formed itself, this compound then began to give off nitrogen very actively. The liquid seethed with a sharp, stinging smell, ‘bringing forth tears in abundance it excites also a very disagreeable sensation in the nostrils and lungs’. When separated from the liquid the compound solidified in a buttery way, and lay pregnant with potential on its dish. This was where the excitement began again. Davy and Faraday put a tiny piece of it into some water and dropped some phosphorus into the basin. Suddenly, bang! – the whole thing exploded, shattering the basin and throwing glass, earthenware, water and the remains of the evil compound up into the air and everywhere. The two men were shocked, but slowly raised their heads above the bench as the clink of precipitated glass fragments died away. They tried once more to tame the beast by reversing the process and adding the compound to the phosphoric solution. This made a sudden flame, but there was no explosion. While they were doing the experiment, Davy blithely reminded his assistant how he had nearly blinded himself the past autumn by trying to heat it up.
Another of Faraday’s jobs that afternoon was to collect the compound together from the various retorts and basins. This he did very gingerly, knowing its explosive power in combination. Davy was not discouraged by the dangers – they seemed to empower him – and this gave confidence to his assistant. Together they set to work again on new ways of attacking the chloride of nitrogen. They tried mixing hydrochloric acid with it in a glass tube, and this caused a rush of gas out of the liquid, filling the tube with bubbles ‘which expanded as they ascended in a beautifull manner to fourteen or fifteen times their original bulk and the tube quickly became full of this gas’. The gas was piped to a trough of water, and its smell and colour immediately revealed it to be chlorine, with a tiny admixture of oxygen. The resulting precipitate was ammonium chlorate. They tried the trick again, this time with nitric acid, and nitrogen alone came off. Then they tried a third time, with a solution of potash. For a fourth time, Davy told Faraday to do it with ammonia, and this immediately produced thick acrid smoke, ammonium chloride, which filled the laboratory, making them both choke violently. Once the smoke had cleared they took some more glass bowls and tubes and tried again with ammonia. The smaller tubes constrained the reaction, but in an instant the whole lot exploded. That brought the experiments to an end, and it was Faraday who had to clear up the mess.
The next day they tried again, this time with yet more violent results. There were four big explosions in the laboratory that day,58 audible throughout the building. Perhaps they caused some alarm, and staff ran downstairs to see what had happened; or perhaps the Royal Institution, being used to the Professor’s stinks and bangs, took little notice. So the Professor and his new boy carried on, undaunted, ducking down behind the bench when they felt the need. They wore glass masks, which were some protection, but the day’s work came to an abrupt end when Faraday had his hand nearly blown apart. The tube he was looking at rather too closely exploded in front of his face, blew violently out of his hand, shattered his mask and took part of his fingernail with it.
Working side by side, the two men were the vanguard, the thin line between the known and the unknown. In his first Elements lecture, Davy stressed the importance of instruments, and the progress that had been made in chemical discovery simply through the development of new, better and yet more ingenious pieces of equipment. ‘Nothing,’ he wrote, ‘tends so much to the advancement of knowledge as the application of a new instrument.’59 Davy was a gadgets man, perfectly at home with glass tubes, bottles and retorts, ground glass stoppers and brass taps and mounts, jointing them together like infinitely variable skeletal remains, with gutta percha, caoutchouc, string or wax or a combination of some of these, though safety was never taken much notice of.
We know nothing of the talk that went on between Davy and his assistant in the laboratory. Davy, who had recently enlarged and published his Elements of Chemical Philosophy lectures, cannot possibly have been silent about them to his companion as they worked together. In a later remark, Faraday described Davy as ‘a mine inexhaustible of knowledge & improvement’,60 and it is likely that that knowledge and improvement will have emerged, by demonstration and example, from the mine from their first day together. Davy will have shown Faraday the importance and efficacy of accurate and accurately-made