Paris. Forty-five years later, after the Second Italian War of Independence, it was replaced by a new legal act. This act was signed in Turin on 24 March 1860 by Napoleon III and Victor Emmanuel II of Savoy, and deals with the annexation of Savoy (following the French neutrality for the plebiscites held in Tuscany, Modena, Parma and Romagna to join the Kingdom of Sardinia, against the Pope's will). A demarcation agreement, signed on 7 March 1861, defined the new border. With the formation of Italy, for the first time, Mont Blanc was located on the border of France and Italy, along the old border on the watershed between the department of Savoy and that of Piedmont, formerly belonging to the Kingdom of Savoy. The 1860 act and attached maps are still legally valid for both the French and Italian governments. In the second half of the nineteenth century, on surveys carried out by a cartographer of the French army, Captain JJ Mieulet, a topographic map was published in France, which incorporated the summit into French territory, making the state border deviate from the watershed line, and giving rise to the differences with the maps published in Italy in the same period. Modern Swiss mapping, published by the Federal Office of Topography, plots a region of disputed territory (statut de territoire contesté) around the summits of both Mont Blanc and the Dôme du Goûter. One of its interpretations of the French-Italian border places both summits straddling a line running directly along the geographic ridgeline (watershed) between France and Italy, thus sharing their summits equally between both states. However, a second interpretation places both summits, as well as that of Mont Blanc de Courmayeur (although much less clearly in the latter case), solely within France. NATO maps take data from the Italian national mapping agency, the Istituto Geografico Militare, which is based upon past treaties in force. As of 2021, the border dispute between the two countries is ongoing. Vallot The first professional scientific investigations on the summit were conducted by the botanist–meteorologist Joseph Vallot at the end of the 19th century. He wanted to stay near the top of the summit to undertake detailed research, so he built his permanent cabin. Janssen observatory In 1890, Pierre Janssen, an astronomer and the director of the Meudon astrophysical observatory, considered the construction of an observatory at the summit of Mont Blanc. Gustave