Kon Obituary Notices of Fellows deceased. 
In Plymouth, 1890, Weldon started his elaborate measurements on the 
Decapod Crustacea, and soon succeeded in showing that the distribution of 
variations was closely like that which Quetelet and Galton had found in the 
case of man. 
His paper “The Variations occurring in certain Decapod Crustacea. 
I. Crangon vulgaris” was, as far as we know, the first to apply the method of 
Galton to, other zoological types than man. In this paper the author showed 
that different measurements made on several local races of shrimps give 
frequency distributions closely following the normal or Gaussian law. In his 
next paper, “On certain correlated Variations in Crangon vulgaris,” he 
calculated the first coefficients of organic correlation, 2.¢., the numerical 
measures of the degree of interrelation between two organs or characters in 
the same individual. It is quite true that the complete modern methods 
were not adopted in either of these papers, but we have for the first time 
organic correlation coefticients—although not yet called by that name— 
tabled for four local races. These two papers are epoch-making in the 
history of the science, afterwards called Biometry. 
It is right to state that Weldon’s mathematical knowledge at this period 
was far more limited than it afterwards became. The first paper was sent to 
Francis Galton as referee, and was the commencement of a life-long 
friendship between the two men. With Galton’s aid the statistical treatment 
was remodelled, and considerable modifications made in the conclusions. 
The defect in mathematical grasp, which Weldon had realised in his first 
paper, led him at once to seek to eliminate it. He set about increasing his 
mathematical knowledge by a thorough study of the great French writers on 
the calculus of probability. He did not turn to elementary text-books, but, 
with his characteristic thoroughness went to the fountain head, and he thus 
attained a great power of following mathematical reasoning, and this power 
developed with the years. He had, moreover, a touch with observation and 
experiment rare in mathematicians. In problems of probability he would 
start experimentally and often reach results of great complexity by induction. 
From 1890 onwards, his knowledge, theoretical and experimental, of the 
theory of chances increased by bounds. 
Weldon’s work at University College commenced in 1891. The house in 
Wimpole Street was taken and, if possible, life became more intense. In 
October came the college inaugural lecture for the session, on the subject of 
the statistical treatinent of variation. This year and the next were strenuous 
years in calculating. The Weldons toiled away at masses of figures, doing 
all in duplicate. At Easter, 1892, they went to Malta and Naples, and the 
summer was spent over crab-measurements at the Zoological Station in the 
latter city, and the first biometric crab paper “On certain correlated 
Variations in Carcinus menas” was issued later in the year. This paper 
confirms on the shore crab the results already obtained on the common 
shrimp. The distributions of characters are closely Gaussian, with the 
exception of the relative frontal breadth, which the author considered 
