In many problems arising from scientific investigations their theoretical formulation leads to differential equations, the numerical solution of which is frequently an extremely laborious process. To handle such problems various mechanical devices have been developed from time to time and the Differential Analyser is one such device, possessing great flexibility in the range of differential equations which can be dealt with by it. Lord Kelvin conceived of such a machine, and the first practical model was designed by Dr V. Bush of the Massachusetts Institute of Technology. Subsequently another full-scale machine was designed by Prof. D. R. Hartree and is in operation at Manchester University. Various small-scale machines have been constructed in this country and mention may be made of those at London University and Cambridge University, designed by Profs. H. S. W. Massey and J. E. Lennard-Jones respectively.

A Former President of the Institute once remarked that whereas the graduation of a mortality table might be considered a specialized technique not required by the practising actuary, the efficient testing of any graduation submitted to him should be an integral part of his actuarial ability. The student anxious to equip himself in this respect encounters considerable divergence of opinion regarding the best method of testing a graduation. There is complete agreement as to the duality of purpose of such a test: smoothness and fidelity to the data are essential factors. But whilst the criterion of smoothness is easily formulated—the run of the second or third differences of qx must show no awkward breaks—the views relating to the tests of adherence to the data are divided between the application of a “mean deviation” rule at each age or group of ages and a purely “practical” judgment based on that elusive virtue, experience.

There are many references to pensions in the pages of the Journal, most of them to the provision of pensions by means of private funds. I am proposing, however, to deal with the provision of pensions and life assurance by means of what are known as group schemes—a comparatively modern innovation. Pensions themselves are not new—in fact, references can be found in history to old retainers and the families of dead retainers living on the charity of the barons. More recently, however, pensions have come to be looked upon not as charity, but as something due as a moral right by virtue of long service. On the other hand, there is still a tendency to consider as charity the provision for dependents of deceased employees.

1. Quantum Mechanics is a portentous name; the alternative—Wave Mechanics—is almost as bad. The mathematics are formidable, the literature large and growing rapidly, and the subjectmatter dealt with is the behaviour of physical things, such as electrons, protons, atoms, and so on. Why, then, should actuaries as such take any interest in the subject?

The recent publication of the Registrar-General's Report on Occupational Mortality in England and Wales in connexion with the 1931 Census has suggested that a Note on this Report and its recent predecessors, with reference mainly to the methods employed in the investigation, may be of use to actuarial students.

Occupational Mortality has been investigated in connexion with every census since 1851. It may at first sight seem a simple matter to take, in each age group, the number exposed to risk in a given occupation from the census schedules and the number of deaths from the death registers, and from these figures to find the rates of mortality. In practice there are many pitfalls. The history of the successive investigations records various attempts to improve the statement and classification of the particulars and the presentation of the results, although there are still a number of known or suspected sources of error, the effect of which can only be estimated roughly, if at all.