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THOUGH rockets have aroused a good deal of public interest during the last few years and a great number of very interesting books and articles have been published about the theoretical side of this new science, little is generally known about the experimental progress that has been made, especially in Germany and the U.S.A. In describing this science—the Americans call it “rocketry”—as “new,” it is to be understood that this term applies only to the mathematics of it. The ordinary powder or “sky” rocket is by no means new, but has a long and very involved history, going back to Hassan Alrammah, called “nedshm‐eddin” (The Faithful) in A.D. 1280, who designed the first rocket‐driven torpedo. But though rockets in general (i.e. the powder rocket, which alone existed previous to 1929) have a history of almost a millennium and have even been of historical importance (Sir William Congreve's war‐rockets), the manufacturers of powder rockets knew nothing about their mathematics. When, for example, in 1928 the German Verein für Raumschiffahrt discussed the problem of exhaust velocities and impulses, its president, Johannes Winkler, asked the largest rocket factories about this information and received the answer that they did not know it and had no way of determining it. Winkler was therefore obliged to take the thrust‐diagram of a powder rocket himself (Fig. 1). This diagram revealed that the thrust of a sky‐rocket lasts for only two‐tenths of a second; this result was really amazing and the most amazed were the manufacturers of these rockets.

Engineering metrology, or dimensional Measurement in engineering as it may otherwise be termed, is a subject which has become of increasing importance to production engineers during the past fifteen years or so. This has been recognized by the Institutions of Mechanical and Production Engineers and it is now include as a subject in their Associate Membership examinations, and also for the Higher National Certificate. Up to the present time, however, books dealing with the subject have been few, and the above book is a welcome acquisition to the number, as it provides an up‐to‐date survey of a subject in which progress is rapid. Mr Hume is well qualified to write on the subject as, in addition to his experience in his present post as Metrology Superintendent of the de Havilland Engine Co. Ltd., he has had a number of years' experience in the Metrology Division of the National Physical Laboratory and at Hilger and Watts Ltd.

Provides direction for researchers and collection developers to locate sources of information on mythical, fantastical and symbolic creatures of world folklore and legends and their documentation in primary and secondary texts. Focussing on mythological animals, gives prominence to the unicorn and the dragon as the two most universal and symbolically important creatures, and to sources which concentrate on their status in folklore and legend rather than to literary works.

The subject of Supersonic Aerodynamics, and indeed of compressible flow generally, is not fundamentally difficult; in fact, some aspects of supersonic flow are appreciably simpler than the corresponding aspects of low speed flow. What makes the subject appear more complicated is the large number of interrelated parameters which are of interest and importance, so that any given relation may be expressed in a large number of equivalent forms. Basically, the aeronautical engineer is largely concerned with the variation of pressure with speed; but in compressible flow, pressure variation implies density variation, and simultaneous variation of pressure and density immediately suggests temperature, the speed of sound, and (with the velocity) Mach number as alternative parameters. Again, many of the ‘constants’, such as the isentropic index y, the specific heats, and the gas constant R, are inter‐related. Since each parameter has its own place and its own field of importance, a multiplicity of forms for a given relation must be accepted; and a handbook in which the important forms are set out for reference becomes essential.

THE Air Ministry have relaxed the British regulations covering the conditions of permissable flying of private aeroplanes so far as the Mignet Pou‐de‐Ciel and the B.A.C. Drone are concerned. Both these machines are of the very small, low‐powered single‐seater type.

The standard method of analysing F.47 take‐off camera films, described in reference 1, is very laborious. It was developed for use when take‐offs were not normally made from runways. Now that most measured take‐offs are made from a runway a simpler method of analysis has been introduced. This requires a fixed camera position at a known distance from the centre line of the runway from which the aircraft is taking off. The essential distances for the take‐off can then be determined from the azimuth angle on the camera record without measuring the image of the aircraft on the film.

DRAGONS represent times far away and marvellous, where none of the ordinary work‐a‐day worries can torment mankind. In Dragon‐Land there are turreted castles, feasts of nightingale tongues, and pomegranates served in golden bowls. Here all men are the bravest of knights, victorious in battle and love, and all women are beautiful and gentle, and wait for lovers in hidden gardens of roses and lime trees, the while they weave tapestries of unicorns and wyverns.

A few years ago, in an effort to promote co‐operation between the two professional associations of librarians in Ireland, a Liaison Committee, consisting of members nominated by the Council of the Library Association of Ireland and members nominated by the Committee of the Northern Ireland Branch of the Library Association was formed. The first fruit of its endeavours was found in the establishment of an Annual Joint‐Conference of the two bodies, the first one being held at Portrush, in Northern Ireland in 1963.

LIBRARIANS in Britain stand at the threshold of great possibilities. Having passed through the ages of the ecclesiastical library, the rich collector's private library, the academic institutional library, and the rate‐supported public library—all general libraries —they have reached the age of the special library. The next will be that of the co‐ordinated, co‐operative library service.

A FEW years ago, in an effort to promote co‐operation between the two professional associations of librarians in Ireland, a Liaison Committee, consisting of members nominated by the Council of the Library Association of Ireland and members nominated by the Committee of the Northern Ireland Branch of the Library Association was formed. The first fruit of its endeavours was found in the establishment of an Annual Joint‐Conference of the two bodies, the first one being held at Portrush, in Northern Ireland in 1963.