IAM Contents OCRd Copy  

Journal of Scientific Instruments (Journal of Physics E) 1968 Series 2 Volume 1



The importance of a knowledge of methods of measurement

With the introduction of a new style for the Journal of Scientific Instruments coinciding with the Jubilee Year of the Institute of Physics it is particularly appropriate that we should review developments in the publication of papers in the instrument field, re-examine the nature and purpose of the journal and endeavour to establish guidelines for the future.

The Journal of Scientific Instruments came into being in 1923 with what we should now call a test marketing issue published by the National Physical Laboratory. In the foreword to that issue Sir J J Thomson, then President of the Institute of Physics, stated:

"It has long been recognised by many workers that a journal dealing with methods of measurement and the theory, construction and use of instruments would have a great value as an aid to research in all branches of science and industry. There is at present no publication in the English language which covers this ground."

It is interesting to note at this stage the coupling of measurement with instruments and the association of these topics with research activities only. E H Rayner, describing the scheme for the journal in the same issue, used the heading above which has become the theme of many physicists and engineers today who feel strongly that insufficient attention is being given to the topic of measurement.

Dr Rayner made the point that:

"Much of the essential information regarding the design and performance of instruments is unobtainable from text books, which in general deal mainly with fundamental principles."

Later, he wrote:

"Many of the makers' difficulties in the design and construction of instruments would be diminished or removed with the assistance of such a journal. The benefit would, however, extend far wider than this as it would be still more valuable directly or indirectly to users, whether individuals, associations, or Government Departments, who are engaged in scientific work. Not only would they obtain assistance as to the choice of the best methods and apparatus but progress in the perfection of the instruments used would be accelerated, resulting in better tools being available to the hand of the worker, by which such an economy of time and improvement in the results would be obtained as cannot fail to have great economic value."

All the elements of the present situation are contained in these statements of 44 years ago. There was a dearth of published information on instruments then; at the present time. although a very large number of papers are published, they probably do not cover the field adequately. Today, assistance is undoubtedly afforded by the journal to both manufacturers and users and it plays no small part in fostering improvements in instruments and methods. The economic aspect of instruments and measurement is probably more important today than when the journal was introduced. One further quotation from E H Rayner's article:

"A publication dealing with methods of measurement and detailed descriptions of scientific apparatus has become as important to workers in science as is a dictionary to the student of languages."

This was a statement of need in 1923 but is one of fact now.

At first sight it may seem curious that there was little discussion in that introductory issue of the ground to be covered by the journal. Clearly and rightly the sponsors must have adopted a `feeling the way' approach. An overwhelming need existed and the essential problem was to get the journal started, leaving its scope somewhat vague and ill-defined but having a positive policy, which has been implemented from the beginning, of publishing only contributions of high quality. At the present time with the very great growth of instrument and measurement activities it is necessary to query what the journal should publish. The fields it covers need to be defined in order to establish its boundaries. Such boundaries are multidimensional for, in addition to classification into the general fields of measurement and instruments, there are other considerations such as the field of application, the technique used and the relationship of the technique or apparatus to the means of measurement (e.g. component part of an instrument, the instrument itself, an accessory or a measurement system).

Many papers attempting to define measurement have been written. One of the most recent expositions of the subject was a discussion entitled What is Measurement?' held three years ago at the Institution of Electrical Engineers and attended by physicists and engineers alike. The variety of proposals made at that meeting indicates the great difficulty of finding a practical definition which is of assistance in selecting papers suitable for the journal. The nearest one can get to a useful definition of a measurement paper is that it should pay attention to the quantitative aspects of an apparatus or technique, including an assessment or indication of the uncertainty in the measurement.

What is a scientific instrument?

So far as can be ascertained the question `What is a scientific instrument ?' has never been debated. `Scientific' could be taken to imply the measurement aspect or alternatively that the operation of the instrument is based on scientific principles. It is not even easy to say what kind of instrument is not scientific for it depends on the circumstances of use. One would not normally think that a musical instrument would fall within this category but a piano could be calibrated and used in an experiment as a digitally operated acoustical signal generator. Certainly in this application its behaviour can be explained in terms of physical principles and there is a quantitative aspect to its operation. The uncertainty may be large but as long as it is known, the instrument may be used for measurement within the limits imposed by that uncertainty. Examples of this type are of course unlikely to occur in practice but point to the nature of the problem.

On the question of the scientific principles by which the instruments operate, it is assumed that these are, in the case of the Journal of Scientific Instruments, physical principles. This distinction was touched on in E H Rayner's 1923 article:

"Nearly all research problems resolve themselves into chemical and physical measurements. Many of the measurements required in chemistry are really of a physical nature, such as measurement of mass, temperature, density, polarimetry and colorimetry."

The recent incorporation of the journal in the Journal of Physics series emphasizes this point.

A reasonably satisfactory definition of a scientific instrument for the purpose of the journal is an apparatus whose operation is based on physical principles and which may be used for measurement. However examination of the journal from the first issue shows that not only are descriptions of complete instruments published but also descriptions of parts of those instruments, devices used in them, experimental procedures involving the use of instruments, preparation of specimens for measurement and many other topics. The scope of the journal cannot therefore be said to be confined to scientific instruments as such but covers all manner of associated matters. The function of the journal is perhaps best described as the publication of information on apparatus, and associated component parts, techniques and accessories, emphasizing particularly the physical principles involved and quantitative aspects of design and performance.

The wider use and greater complexity of instruments

Sir J J Thomson described the journal as of value as an aid to research in all branches of science and industry. At that time the use of instruments in industry was largely confined to the research function particularly if they were of the advanced design and performance justifying publication in the journal. Nowadays, measuring equipment is found in the production side of industry as part of the system controlling the production process or for inspection, environmental testing and quality control. It is also found in the maintenance function for the diagnosis of faults and the verification of performance. Such equipments are no less advanced and significant than the apparatus used in scientific research and a knowledge of their principles of operation and limits of performance may be very useful to the research worker. The fields covered by the journal have thus widened considerably, a process which has been further emphasized by the growth of new industries. When the journal commenced publication nearly all measuring apparatus was made by one close-knit industry the instrument industry. The past forty to fifty years have seen the growth of entirely new industries, one of the most notable from the point of view of measurement being the electronics industry. Radar is an excellent example of a product of a newer industry which is essentially a measuring instrument though it is rarely thought of in these terms.

In step with the growth of new industries has been the growth of complexity in scientific research and in the apparatus associated with it. In the main, such apparatus is constructed in a highly professional manner, carefully engineered to meet stringent conditions of performance, reliability, environment and perhaps even cost. A research satellite and a radio telescope are examples of the more complex apparatus used in scientific research.

Can the journal adequately cover the wider fields of application, the products of the newer industries and the increasing complexity of instruments and systems? It is believed that the four different types of contribution Review Articles, Papers, Notes and Abridged Notes will enable it to do so. Invited review articles can describe the basic properties of complex equipment in physical terms and give an exposition of the measurement and instrument principles involved. Clearly it would not be feasible to publish detailed information covering all aspects of such equipment; the source of such information can be drawn to the attention of the reader in an Abridged Note. Papers can describe the novel parts of a large system or an original technique while Notes can briefly describe the interesting and useful advances.

It is hoped that the journal, in the face of steadily increasing activity, will continue to fulfil its function of recording advances, imparting understanding and drawing attention to the existence of apparatus and techniques in the field of scientific instruments.

H V Beck

Chairman of Editorial Board