In recalling this period in the life of Pierre Curie, between 1883 and 1895, we can appreciate the great progress the young physicist had made while acting as Chief of Laboratory. He had succeeded during this time in organizing an entirely new teaching service; he had published an important series of theoretical memoirs, as well as the results of experimental research of the first order. In addition, he had constructed new apparatus of great perfection--and all this in spite of very insufficient accommodations and resources. This achievement suggests the distance he had traveled since the doubts and hesitations of his early youth in learning to discipline his methods of work, and to derive from them the full advantage of his exceptional capacities. He enjoyed a growing esteem in France, and in foreign countries. He was listened to with interest at the meetings of the learned societies (Society of Physics, Society of Mineralogy, Society of Electricians), where he was in the habit of presenting his communications and where he joined readily in the discussion of various scientific questions. Among foreign scholars who already at this time appreciated him highly, I can name, in the first place, the illustrious English physicist, Lord Kelvin, who joined with him in a certain scientific discussion, and who often expressed for him, from that time on, both esteem and sympathy. During one of his visits to Paris, Lord Kelvin was present at a meeting of the Society of Physics when Pierre Curie made a statement regarding the construction and the use of standard condensers with guard ring. In this statement he recommended the use of an apparatus which involved the charging of the central part of the guard ring plate by a galvanic cell and in uniting the guard ring with the earth. One uses then, as a measure, the charge induced on the second plate. Even though the resulting disposition of lines of the field be complex, the charge induced can be calculated by a theorem of electrostatics, with the same simple formula as is used for an ordinary apparatus in a uniform field, and one has the benefit of a better isolation. Lord Kelvin believed at first that this reasoning was inexact. Despite his great repute and his advanced age, he went the following day to the laboratory to find the young Director. Here he discussed the matter with him before the blackboard. He was completely convinced, and seemed even delighted to concede the point to his companion.[5]