Although made slightly later, this pocket chronometer is very similar to those produced by Henri Motel in the 1830's, from which it only differs by the position of the fusee and the barrel which are inverted and from the balance (see J.-C. Sabrier:La Longitude en Mer à l'Heure de Louis Berthoud et Henri Motel, Antiquorum Editions, Genève 1993, p. 621, fig. 164). One might think that Delépine used to work for Motel among other important makers before setting up on his own, as suggested by the Jury Central of the 1844 Exhibition.Exposition des produits de l'industrie Française en 1844Rapport du Jury CentralM. Delépine, à Paris, rue Coquillière, 27.Nous terminerons la nomenclature des noms des horlogers qui cette année ont exposé des pièces de haute horlogerie, par celui deM. Delépine.Un chronomètre de poche bien exécuté, ainsi qu'un ingénieux compteur pour observation, attestent l'habileté de cet horloger dans la pratique de l'art qu'il exerce depuis longtemps pour le compte d'autrui; aujourd'hui, M. Delépine se présente directement.Le jury le juge très digne d'une médaille d'argent.The secondary error of compensation,or middle temperature errorAlthough, most marine chronometers are fitted with the standard types of compensation balances, their limitations are now clearly understood; it has been recognised for a long time that it has an inherent defect, and that although they compensate the effects of temperature changes, a chronometer in which such a balance is fitted, no matter how carefully it may be made and adjusted, will only keep absolutely correct time at two particular temperatures only, some distance apart. Between those twoemperatures the machine will gain slightly on its rate, while at higher or lower temperatures it will lose. The amount of the change of rate in a chronometer keeping, say, correct time at 50° and 80°, may be as much as 2 1/2" per day at 65°, midway between the two. The name "middle temperature error" is given to this peculiarity of the standard balance, although it is rather a misnomer, since in the above case the amount of the error at 35° and 95° would be considerably greater than that at theiddle temperature, and would increase rapidly as the extreme temperatures diverged further from it.The existence of the middle temperature error having once been established, and the means of correcting it - the acceleration of the motion of the weights in heat as compared with that in cold - having been pointed out, it is natural that the attention of those chronometer makers who were desirous of exhibiting their ability by obtaining a high place in competitions (observatory contests), should have been directed towards some means of removing it. The standard form of balance, however, had beein use for a long period, and had given convincing proof of its power to nullify all but a very small portion of the total error caused by changes of temperature. It is natural therefore, that there were but few makers who considered the possibility of abandoning it completely. The general attention was, rather, directed to the provision of some auxiliary compensation which should remove the middle temperature error while leaving the rims to do their work of nullifying the far greater error whih would otherwise be caused by changes of temperature.The auxiliary which have from time to time been suggested and, in many cases, brought into practical use, may be divided into two classes. The former, which are only intended to come into action at some predetermined temperature, and are inactive above or below it, may be designated as "discontinuous" auxiliaries. The second class, which are always in action, may be designated as "continuous" auxiliaries. The latter involve a rearrangement, or in extreme cases, a reconstruction, of the standardorm of balance. The problem of the middle temperature error was not definitively solved until the invention of the "Integral" balance by Charles Edouard Guillaume, in 1899, which was gradually adopted in Switzerland, between about 1903 and 1912, for chronometers and the highest precision watches of all types, and was then used almost exclusively for them until their production ceased.