## 3 Results
### Optical Telegraph Assembly Process  
The Betancourt and Breguet optical telegraph was a simpler mechanism to assembly than any of the contemporary telegraphs, although in any case it is a structure that when its mast and arrow are aligned has a minimum total height of 9.85 m (if it is true that, depending on the needs of the location, it could reach more than twenty meters high). A precision mechanism of these dimensions requires a fairly careful assembly, and therefore the study of the mechanism and its modeling using CAD techniques has enabled the authors of the article to gain a special awareness of the delicate assembly of the telegraph which we will now describe. In the first place, for the correct assembly of the telegraph, it is necessary to judiciously choose the location of the telegraph station. The operator should have a direct and clear view of the immediate stations. Thus, a location aligned as much as possible with respect to the preceding and subsequent station was chosen, facilitating installation and reducing the possible optical error. Once this location was chosen the plane of the telegraph (plane defined by the circumference described by the indicator arrow) was located as parallel as possible to the planes of the immediate telegraphs, and if this was impossible to measure (there were already compasses at the time), taking the direction perpendicular to the one drawn by the segment that joined the immediate telegraphs. Thus, the frame that held the mast (3) should be perfectly aligned knowing these data, and the structure of the mast should not be raised until a series of elements were placed on it, since once it was lifted it, would be necessary to place a large structure to assemble the rest of the elements. With the mast on the ground, the first element that was to be placed was the winch (9) with its axis, positioning it perpendicular to the structure of the mast. Once in position the shaft had to be fixed by placing the two gimbal joints on the outer faces of the frame, which do not prevent the shaft from rotating but do prevent its axial movement. The next operation was to place the upper wheel (12) with its own axle. In order to do this, the axle had to be placed in its exact location, the wheel housed and finally the metal structure fixed which gave a second point of support to the axle. Thus, the wheel and the winch were still in place to insert the main transmission (11) before lifting the mast. The main transmission was one of the most delicate elements to place in the mechanism. As explained in the description of the invention, the main transmission was formed of a middle zone and two extreme zones. The middle zone was constituted by a hemp rope and the extreme zones were two chains of flat links, and the join of both elements was achieved by means of a tensor that when turned moved its ends closer together. For the assembly of the main transmission one of the tensors needed to be detached from the two ends. Thus, the part of the chain transmission was placed both in the groove of the wheel (12) and in the groove of the winch (9) and once in position the tensor was put in place and the main transmission tensioned (11). This operation had to be performed at least twice since the transmission was double, that is to say there were two main transmissions in parallel. Once it had been verified that, when turning the winch, the upper wheel turned in the same direction, it was time to lift the structure. In order to raise and fix the structure two ropes (10) were necessary, acting as struts of about 12 m in length, which served to give stability to the structure and prevent its swaying. One end of the rope was tied to the head of the mast while the other was attached to an anchor in the ground. Moreover, the structure of the mast has a counterweight on the side opposite the arrow that also supports the mast, which also helps to gain stability in the structure. Finally, once the structure was lifted, it was fixed to the ground by two long anchor bolts.