1792 Lavoisier was forced to resign from his post on the Gunpowder Commission and to move from his house and laboratory at the Royal Arsenal. On 8 August 1793, all the learned societies, including the Academy of Sciences, were suppressed at the request of Abbé Grégoire. On 24 November 1793, the arrest of all the former tax farmers was ordered. Lavoisier and the other Farmers General faced nine accusations of defrauding the state of money owed to it, and of adding water to tobacco before selling it. Lavoisier drafted their defense, refuting the financial accusations, reminding the court of how they had maintained a consistently high quality of tobacco. The court was however inclined to believe that by condemning them and seizing their goods, it would recover huge sums for the state. Lavoisier was convicted and guillotined on 8 May 1794 in Paris, at the age of 50, along with his 27 co-defendants. According to popular legend, the appeal to spare his life so that he could continue his experiments was cut short by the judge, Coffinhal: "La République n'a pas besoin de savants ni de chimistes; le cours de la justice ne peut être suspendu." ("The Republic needs neither scholars nor chemists; the course of justice cannot be delayed.") The judge Coffinhal himself would be executed less than three months later, in the wake of the Thermidorian reaction. Lavoisier's importance to science was expressed by Lagrange who lamented the beheading by saying: "Il ne leur a fallu qu'un moment pour faire tomber cette tête, et cent années peut-être ne suffiront pas pour en reproduire une semblable." ("It took them only an instant to cut off this head, and one hundred years might not suffice to reproduce its like.") Post-mortem A year and a half after his execution, Lavoisier was completely exonerated by the French government. During the White Terror, his belongings were delivered to his widow. A brief note was included, reading "To the widow of Lavoisier, who was falsely convicted". Contributions to chemistry Oxygen theory of combustion During late 1772 Lavoisier turned his attention to the phenomenon of combustion, the topic on which he was to make his most significant contribution to science. He reported the results of his first experiments on combustion in a note to the Academy on 20 October, in which he reported that when phosphorus burned, it combined with a large quantity of air