English: Joseph Vallot (right) and two companions with tent and scientific equipment on the summit of Mont Blanc, France, where they spent three nights n July 1887. Image taken on the third day of their studies by J. Vallot and published with a detailed description of their excursion and travails in "Trois jours au Mont Blanc"" in the Annals of the Club Alpin Francais, 1887. The Alpine Museum of Chamonix identifies the other two men as Chamonix guides, Michel Savioz and Alphonse Payot, so the photograph would have been taken by the only other member of their party, the scientific equipment-maker, F-M Richard. Vallot is wearing a colonial, or pith, helmet which is part of his usual attire in the mountains, and is seen in many other photographs of him. Vallot had installed identical equipment in the Grand Mullets Hut and at his valley base in Chamonix so that simultaneous recordings could be made at three different altitudes. It led to his conclusion that a permanent high-altitude observatory needed to be constructed to enable further scientific investigation to continue.