Baptists are much interested in the departure of one of their members Mr Bruce Etheringyon, B.A. as a missionary to Ceylon, the son of the Rev W D Etherington, M.A. of Babbicombe, for 17 years missionary in India. He carries with him a Kodak camera, a memento of his friends, and the special wishes of the Sunday School and Y.P.S.C.E. with both of which he was identified. He sails on Thursday next.

Mention was made of the zeal and enthusiasm of the late Mr Etherington, who was himself the son of a former Indian missionary.

These early years were happy ones and Ivor recalled them with great warmth. Life in a large family of lively intelligent people formed the grounding of Ivor's education. Before joining the ministry, his stepfather had been a naval engineer and he maintained his interest in matters practical after joining the Church. Their house was full of gadgets which stimulated infectious curiosity. When he was seven, Ivor invented a meccano-based contraption for sending the cruets round the dining table. Unfortunately it was not allowed to be used until after lunch on Sundays! He showed early signs of his lifelong interest in mathematics when he entertained himself during his stepfather's sermons by factorising the hymn numbers.

In recent papers Professor E T Whittaker and H S Ruse have discussed the problem of defining, in a general Riemannian space-time, the concept of distance between two particles, as distinct from that of interval (or integrated line element) between two events. The problem has also been considered by Dr R C Tolman with reference to particular metrics. Ruse's procedure is purely mathematical, being a natural extension of the concept of spatial distance in Special Relativity. Whittaker and Tolman, on the other hand, related their definitions to the astronomical methods of calculating great distances, such as those of the extragalactic nebulae. These methods depend ultimately on a comparison of absolute and apparent brightness, it being assumed that brightness decreases with the square of the distance; or, alternatively, on a similar comparison of absolute and apparent size. It is the purpose of the present paper to investigate definitions which translate that procedure more exactly.

This is a reprint of a beautiful paper by I M H Etherington, written in the early times (1933) of the theory of general relativity. It deals with the very important issue of defining, in the general relativistic context (i.e., in an arbitrary space-time), the notion of (spatial) distance between two particles, this being relevant in the areas of observational astrophysics and cosmology. The paper emerged in the context of an on-going discussion amongst Whittaker, Ruse and Tolman on this central concept. Using very unsophisticated mathematical tools and concepts (normal coordinates and the very notion of tensorial invariance), Etherington managed to prove what is nowadays called the 'reciprocity theorem for null geodesics', which states, roughly speaking, that many geometric properties are invariant when the roles of the observer and the source are exchanged in astronomical observations, this holding in any general space-time, regardless of its geometry.

... were very active in the anti-fascist movement. As the situation in Europe deteriorated, their home became a sanctuary to a large number of refugees seeking to start new lives beyond the reach of Nazi persecution. The Etheringtons, with the help of anyone else they could involve, managed to effect the escape of some 32 people from Germany. Betty even undertook a journey to Germany herself just before the outbreak of war to smuggle back the belongings of escaping refugees.

Several theories of the inheritance of human blood groups have been proposed, but none has been completely satisfactory.

The statistical material of genetics usually consists of frequency distributions - of genes, zygotes and mating couples - from which new distributions referring to their progeny arise. Combination of distributions by random mating is usually symbolised by the mathematical sign for multiplication; but this sign is not taken literally for the simple reason that the genetical laws connecting the distributions of progenitors and progeny are inconsistent with the laws governing multiplication in ordinary algebra. ... However, there is no insuperable reason why the genetical sign of multiplication should not be taken literally; for it is possible with any particular type of inheritance to construct an "algebra" - distinct from ordinary algebra but of a type well known to mathematicians - such that the laws governing multiplication shall represent exactly the underlying genetical situation. These "genetic algebras" are of a kind known as "linear algebras," .... It is not suggested that the use of ordinary algebraic methods in conjunction with the specific principles of genetics will not lead to correct results. It seems, however, that the systematic use of genetic algebras would simplify and shorten the way to their attainment, and perhaps enable much more difficult problems to be tackled with equal ease. The construction of genetic algebras has been described in a somewhat abstract way in a previous paper (Etherington, 1939), .... Here I propose to consider the symbolism more from the geneticist's point of view, applying it to some simple population problems, without going into the details of the mathematical background. It will be recognised that the current treatment of such problems does in reality make use of genetic algebras without noticing them explicitly. By elaborating the symbolism and adapting it to more complicated genetical premises..., it should be possible to avoid the laborious complexity which other methods in such cases would involve. Only elementary mathematical knowledge is assumed, and it is hoped that this paper will be found understandable by geneticists whose mathematical knowledge is quite limited. ... I am indebted to Dr J Ffoulkes Edwards for a lengthy correspondence in which this paper germinated ...

I wish that this thesis may not be judged as a finished achievement in biological investigations but may be judged primarily as a contribution to algebra, suggested by biological problems, and perhaps having possibilities of applications beyond the simple ones so far demonstrated.

The algebras considered here are non-commutative and non-associative (i.e. not necessarily commutative or associative) in multiplication, and are linear over a field which is assumed commutative, associative and non-modular. They are not necessarily of finite order. Train algebras arose in the study of genetic algebras, which provide simplified mathematical models of the transmission of genes in sexual reproduction.

I initiated the study of genetic algebras in several papers between 1939 and 1951 ... . I was intrigued by the unusual properties of these algebras, which were quite unlike anything in the literature. I also thought that, from the point of view of geneticists, the subject had a future. My belief was fortified by kindly letters from J B S Haldane and Lancelot Hogben, and still more by the appearance of R. D. Schafer's seminal paper in 1962 in 'Mathematica Scandinavica'; also by Olav Reiersol's paper in 1949 in the 'American Journal of Mathematics'. Over the years, from 1966 onwards, many papers about genetic algebras have appeared and are still appearing. Frankly, I am unable to keep up with them, so that I am no longer the expert on the subject.

As a student at Edinburgh University in the early 1960s I very much remember Dr Etherington (or Dr I H M Etherington but certainly not Ivor Etherington). He had a slightly bumbling style as a lecturer but his lectures were always well prepared and interesting. He came across as a quiet (and very shy) but kind man for whom, over the years, I had a high regard. I was pleased to note his promotion from Doctor to Professor.

He had a wide range of interests in all manner of things, a sharp intellect and an impish sense of humour. He had a reading knowledge of seven foreign languages, not to mention Esperanto, and harboured ambitions to read (though not to speak) Chinese. He obtained some books on Chinese and a Chinese mathematical dictionary, confessing in typically modest fashion to making just a little progress with the language. In some autobiographical notes he left, he wrote 'If I live, as planned, to age 100, I may just manage it with a year or two to spare. Anyhow I guess you can sell these books and get more than I paid for them'. He also had a lifelong love of music and particularly enjoyed playing the piano, especially Beethoven sonatas. He had learnt the rudiments of piano-playing from his friend John Ffoulkes Edwards and started to teach himself, but later received more formal instruction on the insistence of his step-grandmother.