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IN the two‐dimensional case the configuration shows a wake which forms a discontinuity in the flow, being bounded by contact vortices δγi1 and δγi2 which have as resultant a vortex δγi (FIG. 12). For there to be lift: δγi2<0, δγi1>0, δγi<0. There corresponds to each vortex δγi a vortex on the aerofoil δΓi of the same sign, and in addition a vortex Γ corresponding to the free stream potential, without jet.

The circulation which is established around an aerofoil section which has i trailing edge jet, and thus also the lift, is directly dependent on a trailing edge condition similar to the Joukowski condition in conventional steady and unsteady flow. There is a downwash made up of elementary vortices but in this case the vortex density is not zero when the sheet extends to infinity. The problem is govcrnec by an equation similar to the Wagner equation, into which is introduced the curvature of the downwash at the trailing edge. Certain precautions have to be taker when calculating this. The law governing the movement of the elementary vortices in the downwash plays a very important part. It is directly dependent on the viscous damping of the vorticity. This effect has also had to be taken into consideration, and the drag law of the jet behind the nozzle established. Other results follow concerning the solution of the transient case, and the determination of the circulation up to the moment of reaching its steady limit value, which is achieved in finite time. The velocity distribution on the aerofoil can be found at any instant, and thus also all the properties concerning the aerodynamic forces. The method has been applied to two cases, and a comparison is made with experimental results. An extension to the case of a conventional aerofoil (without jet) is possible; in this case the circulation must have a slightly lower value than in the Joukowski case, the difference depending on the Reynolds number. There is a potential drag resulting from the existence of the downwash and its loss of momentum. In Part II the finite span case is considered. The basic equations are established, and an approximate solution of the steady How case found, where the distribution of circulation is elliptical. A wing interrupted by a fuselage is also considered, and comparison with experimental results given.

IT is known that the Library Association Council has devoted watchful care to the position of libraries in the event of war. As we write, the international situation is as dark as it has been at any time since 1919, and many have that calm, cold feeling that there is nothing to do but to tighten our belts and stand againt the onslaught. Even if that is still avoided, as all who listened to Lord Halifax trust it may be, there should be active protection of the library service which is one of those things which might so easily go under in a time of stress. The Library Association has done well in submitting to Government that experience in the last war proved the value of libraries for information and as a factor in the morale of the people; that their services should, so far as possible, be maintained even during hostilities; that there would be need of library provision for people, and especially for children, “evacuated” to areas where the existing library provision might often be inadequate; and that library buildings should not be used for purposes for which they are unsuitable, seeing that there will be many halls, schools and other buildings that would be better for food‐control, recruiting and so on.

Unter intelligentem Tourismus soll hier ein Tourismus verstanden werden, der möglichst wenig negative Wirkungen auf die Umwelt (vor allem die Landschaft, aber auch Wasser, Luft usw.), die Wirtschaft und die Gesellschaft hat. Im folgenden soll primär auf die Umweltwirkungen des Tourismus eingegangen werden, während seine Wirkungen auf die Wirtschaft und Gesellschaft vernachlässigt werden.

These substances, resulting from the constant building‐up and breaking‐down of living tissues, have most friendly relations with their host, although antagonists—antimetabolites—appear now and then and disrupt their functions. In some of the inborn errors of metabolism, the antagonism is permanent and unless replacement therapy occurs at a very early stage, it interferes with physical and/or mental development. That metabolites from other sources introduced into a host could be extremely toxic was amply illustrated when a metabolite of certain strains of Aspergillus flavus, a fungus commonly found in peanuts and other vegetable seeds, caused severe losses to turkey breeders a few years ago. In 1960, it was discovered that the toxic principle was aflatoxin, which had a number of components and that all farm and laboratory animals, with the exception of sheep, were sensitive to it. Now, it has been confirmed that pure aflatoxin added to a normal laboratory diet is carcinogenic. (J. H. Butler and J. M. Barnes, 1963, Brit. J. Cancer, 17, 699.) Cows fed on highly toxic meal secreted a milk factor which proved to be toxic to ducklings. (H. de Iongh, R. O. Vles, and J. G. van Pelt, 1964, Nature, 202, 466.)

Paul Anderson has been appointed to the board of Durr Ltd., Warwick, and Director in charge of the Paint Finishing System (PFS) Division.

With the drastically changed pattern of the retail food trade in recent years in which the retailer's role has become little more than that of a provider of shelves for commodities, processed, prepared, packed and weighed by manufacturers, the defence afforded by the provisions of Section 113, Food and Drugs Act, 1955 has really come into its own. Nowadays it is undoubtedly the most commonly pleaded statutory defence. Because this pattern of trade would seem to offer scope for the use of the warranty defence (Sect. 115) in food prosecutions it is a little strange that this defence is not used more often.

Rita Greer describes her very successful, one woman research to produce attractive and appetising food for a gluten free diet. As an artist, her approach to the problem was unique. If an engraver can produce forgeries of bank notes, why, she asked herself, should not an artistic cook be able to produce forgeries of ordinary food to meet the needs of a special diet?

Words like Participation tend to be labels stuck on generalities, signifying nothing. They are used as verbal bromides by publicists anxious to cover harsh realities with an attractive veneer. As a rule, once they have served their purpose, they are conveniently forgotten.

Slyme Green College of Further Education stands to the north of the town on the edge of a vast new trading estate. A glistening block of glass and concrete, it was opened a little over two years ago by Alderman Joseph Soap, Mayor of Slyme Green and Chairman of Governors. You follow a trail of litter up the drive, past the savaged saplings to the pool in the forecourt, a feature full of orange peel and little bits of stick. In the middle on a stained slab of slate stands a thing in metal, symbolising the Ministry giving birth to Technical Education. And very painful, too. This caused a furore locally, was featured in ‘Panorama’, and nearly cost the Labour Party four seats in the borough elections. (Soap, Chairman of the Education Committee: ‘I was never consulted’.)