Betancourt retakes his work on the optic telegraph that he had already planned with his friend Breguet. On November 13th they both presented the memoir and the plans of their prototype of an optic telegraph to the Directory, with a favourable reception by Prony. A polemic began with Claude Chappe the inventor of the first telegraph –which was already working in France- who sees the use of his invention in danger. In January 1797 the Directory filed the expedient and the new invention of Betancourt and Breguet did not carry on.

Betancourt, not liking the way things were going, decides to return to Spain and carry on with the expedition to Cuba, of which Lanz had already pulled out of due to an illness.

Meanwhile, in November 1796 Peñalver in Spain receives an economic help for a publication about the Gabinete de Máquinas, whose first volume they tried to print in 1798 without being able to do so; it will be released in the form of loose plates and only a few will be edited.

At the end of January 1797 Betancourt and the industrialist Périer obtain the exploitation patent of an hydraulic press, invention of the former, in fact it is no more than an improved machine based on the Bramah press [See Description of the hydraulic press of Mr Bramah] that the Canarian engineer had seen in England.

Before leaving France Betancourt leaves Breguet as representative for his economic affaires in the country.