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THE function and behaviour of a lubricant on certain parts of an internal‐combustion engine is so complex that the knowledge on this subject is still very incomplete. After several years of experimentation both with specially designed apparatus and with actual engines, the authors of these notes have reached certain conclusions which they will here endeavour to record. Some of the conclusions must, nevertheless, be regarded as opinions only, since lubrication in all its forms is not yet an exact science. For instance, the exact means by which oil lubricates a piston‐ring reciprocating within a cylinder remains very obscure. The action of the lubricant at the rings and in some bearings, such as at the gudgeon‐pin, does not lend itself to mathematical treatment because the conditions are not constant. The alternate sliding and stopping is not a strictly continuous process, and neither the “fluid” nor the “boundary” theories of lubrication can be satisfactorily applied.

IN an article published in the February issue of AIRCRAFT ENGINEERING the writers discussed the influence upon lubrication of various physical and chemical characteristics of lubricants, practicable and otherwise.

It is almost one hundred years to the day that G W Hunt wrote these words. Apart from writing these words and the fact that Hunt was a close friend of Keats and Shelley, I can find no trace of anything else exceptional in this man's life. Yet, almost 100 years later, his words bear so much truth that they have been resurrected, not only for the purpose of my article, but as a slogan for the shipbuilding industry in the UK. For years in this country the shipbuilding industry has seldom had ships, always had men and never had money. Profits in the industry have declined more than in any other, and relationships within the industry deteriorated to such an extent that the business of building ships as far as the UK goes might just as well be buried — at sea. It has always proved to be a newsworthy industry, whether it be the birth of UCS or the survival of Harland & Wolff in Belfast despite the environmental trauma outside its gates. In the past few years we have seen dock sides become dormant and the employees, far from sleeping, have become militant to the point of defying the law. All through the furore of containerisation, when economic arguments were the main consideration, the saddest and most costly of these factors was played down: the greatest jackdaw industry in the land — pilferage.

IN certain instances, where Diesel engine speeds have been taken above 2,000 r.p.m., quite an unexpected degree of trouble has been met with in big‐end bearing design. Bearing areas and connecting‐rod stiffness have been increased in the oil engine, as compared with the petrol engine, so as to allow for the higher gas pressure in the former type, but in spite of this, the white‐metal linings in some engines have been found to break up in the course of long running.

TO answer the question, “What are the best fuels for aircraft?” might seem at first sight neither more nor less difficult than to say, What are the best fuels for motor cars? There is, however, one added factor, namely, that of weight, and this adds greatly to the complexity of the question.

THE original work of Mr. H. R. Ricardo in 1919 showed some of the technical advantages of using fuels of high anti‐knock value. Since this time the development of aero‐engines in respect of power output and economy has depended more upon the fuels available than upon any other factor. Considerable progress has been made in the direction of improving the anti‐knock value of petroleum spirits, which constitute the bulk of the fuel used in aviation throughout the world. However, until very recently this progress had not been very rapid, and as Mr. Ricardo showed, far greater improvements in anti‐knock value could be achieved by the use of other fuels such as benzol, toluol and alcohol. On the octane scale benzol and toluol have a blending value by the C.F.R. motor method of about 90 in concentrations up to 50 per cent; that of alcohol being about 105. This is shown in Fig. 1, from which it will be observed that two curves are given for ethyl alcohol, one being obtained under motor method conditions (mixture temperature 149 deg. C.) and the other with the same heat input as required for a normal aviation gasoline. By this means the additional advantage of the higher latent heat of the alcohol blends is shown. Neither benzol, toluol nor alcohol is produced in very large quantities, and moreover, in times of national emergency they are likely to be required for purposes other than for use as aviation fuels.

NO one interested in the question of lubrication can fail to appreciate the contribution of Messrs. Thornycroft and Barton to this subject. With the validity of most of the experiment and with the conclusions drawn from it, we can all agree, but a wider and more impartial view of the whole subject makes one hesitate to accept, at any rate in their entirety, the conclusions drawn from one or two points.

As a conclusion to this series I want to include a mention on some of the work PA have been undertaking with hospital groups, particularly with the Sydney Hospital in Australia. With the soaring costs of the National Health Services worldwide, in spite of many gaps in the service even in the developed countries, this study indicates the considerable potential for improving the value obtained for money spent by hospitals. The study also indicates that reduction in cost and improvements in efficiency came as by‐products to improving hospital management for the benefit of patients. To obtain these benefits there had to be considerable emphasis on training, education, encouragement and involvement. With these components, attitudes were slowly changed at all levels within the hospital.

Orders Placed during the Months of July and August this Year

THE following list of contracts placed by the Air Ministry during March is extracted from the April issue of The Ministry of Labour Gazette:—