Introduction. With the imminence of non-destructive landings of small instrumented payloads on the moon, many suggestions are being put forth as to methods of analyzing its surface. It is the purpose of this report to present a body of information which, it is hoped, will be useful in examining the feasibility of an early nuclear experiment to determine the elemental constituents of the lunar surface. The reasons for considering a nuclear approach is that it may be possible to perform an analysis without complex and elaborate manipulations, sample preparation or rigid geometrical constraints. Only those experimental designs which come within the presently-available or very-near-future general boundary conditions on weights, power, vehicles, etc., are discussed. The general approach is to consider the bombardment of the lunar surface with various nuclear beams and to examine the possible nuclear reactions which are know to be dependent on the mass and charge of the irradiated material. Then, those resultant radiations are sought which can be detected with little-or-no loss or distortion of the information which they contain.

This is a selected bibliography of books, journal articles, and unclassified reports published on the state of matter at high pressure from 1950 to October 1959. Sources consulted were: Physics Abstracts, Nuclear Science Abstracts, Geophysical Abstracts, Library of Congress Monthly Index of Russian Accessions, and Chemical Abstracts.

The development of high-energy charged particle accelerators such as the Bevatron and of improved nuclear-event detection devices such as the Berkeley 72-in. hydrogen bubble chamber has greatly increased the need for high-speed data reduction of nuclear events. Full exploitation of the potential of the 72-in. bubble chamber demands a very high-speed analysis system. This paper describes an approach to such a system.

Introduction. The von Neumann stability criterion is used to analyze the stability of three types of difference schemes for partial differential equations. It is shown that, contrary to the usual rule of thumb, there exist symmetric implicit schemes for a class of equations which are unstable for every mesh-ratio but that this cannot occur if (a) there are fewer than three "space" variables or (b) the difference expression is used to approximate the mixed derivative.

At the Montreal colloquium Ahmed urged Oliver to make batches of emulsion which would differ only in gelatin concentration. At that meeting Oliver had reported finding a correlation between grain size and silver ion concentration during precipitation, as implied by Perfilov and his Leningrad colleagues. Ahmad felt that one should have more precise knowledge of the relative influence of gelatin concentration of grain sized and their distribution. The incentive is that, in spite of excellent progress in many laboratories and in consistently dependable production from industry (to us, of course, Ilford is most familiar), nuclear emulsions are needed in a wider variety of sensitivities and grain sizes. Available nuclear emulsions have limitations in sensitivity, discriminatory ability, and concentration of hydrogen nuclei. Fine grain size enhances discriminatory ability. An incentive is also in that there is a shortage of literature dealing with the processes involved in the fundamental steps of emulsion production.

The principal types of particle accelerators are described briefly according to operation and history. Known operating particle accelerators are listed with their pertinent dimensions.

This bibliography lists selected articles on molybdenum, niobium, tantalum, tungsten and uranium oxide in the journal literature of the U.S.S.R. The following sources were used and also are noted after each citation, Special Library Association Translation monthly 1959-June 1960, U.S. Library of Congress Monthly index of Russian accessions 1955-June 1960, U.S. Office of Technical Services Technical translations 1955-1958.

"This bibliography lists selected books, articles, and unclassified reports which have appeared in the following abstracts and indexes between August 1959 and December 1960."

To properly assess the "sensitivity" of explosives systems under impact conditions we must obtain detailed information on these mechanisms by which explosives are ignited by impact. It is necessary to know which impact conditions represent the greatest hazard to explosive materials, as well as to know for a given impact condition the relative responses of explosives of interest. I should like to describe to you a program sponsored jointly by the Department of Defense and the Atomic Energy Commission to attain this type of information. A wide variety of impact experiments have been conducted using geometrical arrangements of explosive, plastic, and metal which are relatively simple compared to complete ordnance systems. All of these tests have employed billets of explosive fabricated by standard production techniques, and the billets have been sufficiently large that ignition, once started, has something of the same opportunity to grow or decay as in full scale ordnance assemblies. From these relatively simple tests there has accrued much new useful information on the behavior of explosives under impact. With this new information providing a base from which to work, it is hoped that theoretical calculations on impact phenomena will in the future make a bigger contribution to …

In the course of modern physics research, the need frequently arises for storage of large quantities of electrical energy which can be periodically discharged at high peak power into a load. Until recently, the homopolar machine has been an intriguing device having considerable academic interest but little practical value. In recent years, successful machines have been developed to utilize liquid-metal brush systems. The liquid-metal brush overcomes all the problems associated with current collection power loss, frictional loss, and limiting peripheral velocity. Consequently, these machines are now worth serious consideration where high-current dc generation is required. The main purpose in setting up a homopolar generator test program was to establish the limits to which an essentially standard commercially available generator of this type could be pushed.