Lavoisier's chemical research between 1772 and 1778 was largely concerned with developing his own new theory of combustion. In 1783 he read to the academy his famous paper entitled Réflexions sur le phlogistique (Reflections on Phlogiston), a full-scale attack on the current phlogiston theory of combustion. That year Lavoisier also began a series of experiments on the composition of water which were to prove an important capstone to his combustion theory and win many converts to it. Many investigators had been experimenting with the combination of Henry Cavendish's inflammable air, which Lavoisier termed hydrogen (Greek for "water-former"), with dephlogisticated air (oxygen) by electrically sparking mixtures of the gases. All of the researchers noted the production of water, but all interpreted the reaction in varying ways within the framework of the phlogiston theory. In cooperation with mathematician Pierre Simon de Laplace, Lavoisier synthesized water by burning jets of hydrogen and oxygen in a bell jar over mercury. The quantitative results were good enough to support the contention that water was not an element, as had been thought for over 2,000 years, but a compound of two gases, hydrogen and oxygen.