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The third term has been expressed as but in wind tunnel work it is often more convenient to measure were the omission of the dash signifies that the moment is now measured about a wind axis. The two quantities are very closely related and the measurement of one tells us almost as much as if the two were known. The latter, however, tells us either directly or indirectly what effect the addition of fin and rudder will have on the autorotation properties of the wings alone. The damping of fin and rudder being due essentially to the air flow meeting them at an angle on account of the rotation it should theoretically be possible to deduce this dynamic quantity from a simple static test of moment due to yaw angle. An experiment to test this was carried out several years ago but the static test did not give any approximation to the truth. This was ascribed at the time to the shielding of fin and rudder by the tail plane in the rotative experiment and subsequent work has amply confirmed this view. It is now known that shielding by the tail plane is by far the most important factor in determining the efficiency of the vertical surfaces at high angles of attack.

Rather more than four years ago there was published in AIRCRAFT ENGINEERING the first description of a novel type of tail, described by its inventor as an oblique empennage, to which we gave the name “The Rudlicki Vee Tail.” For it were claimed advantages in resistance, weight and improved field of fire to the rear. In a leading article we hazarded the suggestion that it might also have valuable qualities as an anti‐spinning device. This suggestion aroused interest at the time and we understood that official investigations were to be made to test its soundness. Only recently we learnt that in fact these experiments were made at Farnborough, but for some reason the results were never published. They did not support the view we put forward and the vee tail appears not to have the qualities in spin that seemed possible. In spite of the lapse of time we got into touch with Mr. Stephens, who carried out the experiments, and he has kindly written this account of them for publication here, as we feel that some readers may still be interested in having the matter cleared up even after this long interval

THE first recorded mention of a project for the construction of a vertical wind tunnel appears to be contained in the Report of the National Advisory Committee for Aeronautics for the year ending June 30, 1928, when the advantages of a tunnel of this type for spinning experiments were pointed out and the decision to build one announced. The fact that it had been started was mentioned in the following year's report and its completion announced in the report for 1930. A full description of this tunnel, which forms part of the research equipment at the Langley Memorial Laboratory, was published in AIRCRAFT ENGINEERING, Vol. IV, February, 1932, pp. 29–31. A brief description of the R.A.E. vertical tunnel was given by Mr. A. V. Stephens in AIRCRAFT ENGINEERING, Vol. III, September. 1931, at page 215.

Experiments with Modified Tail Units.—Experiments have been performed with 1/15th scale models of the original single‐seater fighter and 1/20th scale models of the Bristol Fighter with a view to improving their spinning properties by redesigning the tail unit. The experiments with the fighter models were mainly directed at investigating the spinning characteristics of the original and deepened models to see whether the overall effects of the deepened fuselage and raised tail plane would bear out the encouraging conclusions drawn from the wind tunnel work. The scope of the experiments was somewhat limited, but all results indicated that slower and steeper spins and very much more rapid recoveries might be expected from the deepened fighter.

THE purpose of this paper is to give some account of the work on spinning and the progress which has been made since S. B. Gates and L. W. Bryant presented their paper to the Society, which was published in more comprehensive form by the Aeronautical Research Committee as R. & M. 1001.

A review of some recent papers on a variety of aspects of interlibrary lending in the United States, Canada, Australia, Scandinavia and East and West Germany. Particular attention is paid to the problems of net lenders, to possible solutions such as improvements to union catalogues, an efficient library network or centralised collections, and to the associated problems of copyright legislation and publishers. It also looks at the value of telex and the lending of non‐book media.

ORIGINS THE Department of Aeronautical Engineer‐ing at The Queen's University was founded primarily to stimulate the flow of local talent into the aircraft industry of Northern Ireland. With the transfer of the whole of the resources of Short Brothers and Harland to Belfast in 1947 and their subsequent development, the aircraft industry had come to represent a considerable fraction of the engineering effort of the Province. It was thus to be expected that the only University in Northern Ireland should concern itself with the special needs of this exacting branch of engineering. The University had long had a School of Engineering forming part of a Faculty of Applied Science and Technology. The engineering disciplines were civil, mechanical and electrical, and the mechanical courses in particular had been adapted to some extent to meet aeronautical needs. But it was only natural that there remained a demand for a separate department, providing a degree course devised specifically for aeronautical engineers. In the event the Department of Aeronautical Engineering was established in 1956, after close consultation with Short Brothers and Harland, who have given it both generous support and willing co‐operation ever since.

March 16, 1970 Negligence — Duty of care — Damage to electric cable by workmen building wall on road — Resulting power failure in near‐by factory — Damage to plant and machinery and loss of day's production in factory — Claim for damages by factory owner — Whether damage too remote — Liability of defendant — Whether actionable nuisance.

ON another page of this issue will be found a description of a novel arrangement of the tail surfaces of an aeroplane which we have christened the “Vee Tail.” Known in Poland, the country of its origin, as an “oblique empennage,” it is, in fact, in the form shown, simply a pair of horizontal surfaces, fixed and moving, set at a positive dihedral angle of about 30 deg. to each other. In itself there would be nothing particularly remarkable in this, but the significant point of the arrangement is that it dispenses with the fin and rudder, there being no vertical surfaces at all.

THE problem of the spinning nose dive has been the subject of much experimental work in recent years. These researches have been chiefly prompted by the fact that the spin has existed as a potential source of danger since the earliest days of flying. Innumerable accidents have been caused by machines getting into a spin near the ground, generally as a result of engine failure while climbing steeply. Modern tendencies in design have also led to certain types of aeroplane being unable to recover from prolonged spins under adverse conditions of loading. Accordingly, the immediate object of this work is to gain a sufficient knowledge of the principles underlying the motion to enable designers to produce aeroplanes which will not fall into an involuntary spin, however careless or inexperienced the pilot may be; and further, to ensure that an immediate recovery from any spinning motion will be possible without an undue loss of height. There is a growing body of opinion that the spin is no longer necessary as a tactical manoeuvre for fighting aircraft. The ultimate object of research on spinning may thus be the evolution of an aeroplane which will not be capable of spinning in any circumstances.