Betancourt begins to assemble the collection of instruments as soon as he gets to Paris. The polemic about the optic telegraph is reopened and Betancourt & Breguet write out a Memoir on their apparatus: Mémoire sur un nouveau Télégraphe et quelques idées sur la langue télégraphique.

The Académie des Sciences of Paris forms a commission of experts –Laplace, Lagrange, Borda, Prony, Delambre, Coulomb and Charles- to compare the two telegraphs: the one of Chappe and the other of Betancourt & Breguet. After an examination at the Observatory the commission praises the Betancourt & Breguet model and decides to publish a report on it: Rapport sur un nouveau télégraphe, de l’invention des citoyens Bréguet et Betancourt.

However, Chappe’s influence is strong and their invention was never put into practice in France. In Spain, on the other hand, there was a big interest in Betancourt & Breguet’s invention; and they proceed to use it in the installation of the first telegraph line. This initiative leaves the trip of the Canarian engineer to Cuba suspended who then, passes to be in charge of this affair.

In May and September 1798 –and in April 1799- four booklets are published in the Gaceta de Madrid of the Descripción de las máquinas de más general utilidad que hay en el Real Gabinete de ellas, establecido en el Buen Retiro written by López de Peñalver. The first one is about Bramah’s hydraulic press, the second booklet is dedicated to the description of a machine to make nails, the third one is double: a description of a machine able to wind several hanks/skeins at the same time, and, also, a description of sea port cranes; and the fourth booklet (where there was a change of draughtsman and technique, Mariani substitutes Sureda) is dedicated to three kinds of machines: description of several wheelbarrows, of a cart to transport earth and of a machine to make braid. Finally there are several loose plates of machines drawn by Mariani that were never published in booklets with a descriptive text.

The edition of these booklets was interrupted through the lack of answer from the public.