A History of Kaye and Laby
Does that title need explanation? No one who uses the book would ever call it "Tables of Physical and Chemical Constants", and any reader who is not familiar with its customary description may reasonably skip what follows here. But how many of those who do know it remember that it had a sub-title, "and some mathematical functions"? They do not need to remember any longer for that has gone from the 16th edition.
The first thing that struck me when I started to prepare this article was that Kaye and Laby was a young man's book, for the authors were both 31 when the first edition was published in 1911. That contrasts with recent editions for I suspect that few of today's contributors are as young as the original authors. It was a Cambridge product. Kaye and Laby were students in the Cavendish laboratory and they collected data needed in their researches from widely scattered sources; friends suggested that the information was sufficiently useful for it to be worth publishing, and the Tables were the result.
G.W.C.Kaye went up to Cambridge in 1905, graduated in 1908 and became personal assistant to J.J.Thomson. He left the Cavendish in 1910 to join the National Physical Laboratory (NPL) and, apart from the interruption caused by the 1914-18 war, he remained there until his death in 1941.
When he joined NPL one of his first jobs was in connection with a proposed silica standard of length - stable enough maybe, but obviously fragile, and there does not seem to have been any follow up to the paper Kaye wrote on the subject. Then came the war, and involvement ultimately with the Air Ministry as chief inspector of materials.
When he returned to NPL he became head of the Physics Department, which included work on heat, thermometry, optics and radiology. He initiated work on acoustics. Radiology and acoustics seem to have been his prime personal interests, and as the years passed he became involved with numerous committees and commissions on these subjects. He was greatly concerned with quantifying radiation dosage and the protection of those who worked with radium and X-rays, and he took a leading part in establishing the British Institute of Radiology. In an obituary note, J.A.Crowther commented that the success of the negotiations for this last was due not a little to Kaye's tact and commonsense, and above all to his friendliness - "It was impossible to quarrel with Kaye; and it was almost impossible to quarrel with anyone else if Kaye were present". In another notice, E. Griffiths wrote, "He was at heart an experimentalist, and though he did not despise theory, he had an impatience with it, and could always find more pleasure in a neat experimental proof than in a logical deduction."
T.H.Laby was an Australian, effectively self-educated. Because of family misfortune Laby had to make his way by force of character and ability. His early studies impressed sufficiently for him to obtain a post in the Chemistry School of Sydney University and in 1904 he was awarded an 1851 Exhibition. All this without having obtained a degree, which he was eventually awarded in Cambridge for his research. On arrival in England Laby first went to Birmingham to work with Poynting, and Poynting recommended him to move to Cambridge and the Cavendish. There he met Kaye and also G.A.Carse, who is named in the preface to the first edition of the book as having shared in its inception. He published papers jointly both with Kaye and with Carse.
Laby left Cambridge for New Zealand in 1909 to become professor of physics at Wellington University. So the two authors were not together for very long, and their collaboration during most of the life of the book while they were responsible for it was at a distance such that meetings between them could only have been infrequent and an exchange of letters took 3 months or more. We may guess that they had at least completed planning the first edition by the time Laby left for his new post and that for future editions they were each responsible for a distinct part of the compilation. I have not found any statement to that effect, but it is clear from the passage quoted later in this article that Laby was responsible for the chemical data. By the 9th edition (1941) the practice of identifying contributors by their initials had been adopted (now, in 16th edition, by names in full).
Laby remained in Wellington until 1915, when he was elected to the chair of natural philosophy in the University of Melbourne. He remained there until he resigned in 1942; he died in 1946. In an obituary notice H.S.W.Massey wrote - "His primary interest was in precision experimental physics, but this did not prevent him from realizing the importance of other branches of the subject. Thus he was keenly aware of the importance of theoretical physics and encouraged any students with a bent in that direction. .... It is difficult to say in which field of precise experiment Laby was most interested; thermal conduction, mechanical equivalent of heat, X-rays, geophysics, scientific radio, all occupied his attention and were a continual source of research problems for his students and assistants." Laby also played an important part in various developments in Australian science such as the organization of the radium supply for hospitals and the formation and operation of the Radio Research Board. After the outbreak of war he was chairman of the country's Optical Munitions Panel, which helped to establish a productive industry.
In recent years new editions of Kaye and Laby have appeared at about 10-year intervals, but while the original authors were responsible successive editions sometimes followed at only 2-year intervals, and only twice were there more than 5 years between successive editions. The 10th edition (1948), which did not appear until after the war and after the deaths of Kaye and of Laby, was completed by Laby's daughter, Jean Laby, who was member of the staff of the Melbourne School of Physics.
For preparation of this article I have been able to consult several copies of Kaye and Laby and the most obvious difference between them is their size, which has steadily increased, notably since they ceased to be under the control of the original compilers. The 1st and 3rd edition (1911,1919) have 153 pages, the 7th (1932) 163, the 10th (1948) 191, the 12th (1959) 231, The 14th (1973) 386, the 15th (1986) 476, and the 16th (1995) 611. Page numbers are not the whole story because the format was changed with the 14th edition and the pages of that and subsequent editions are about 25% larger than those of the earlier editions. A simple calculation gives us the result that Kaye and Laby's size has increased about five-fold since it was first published.
Another numerical comparison that may be made is of the total number of contributors. In the first few editions there are ten names of people (including those of Kaye and of Laby) who contributed to the volume whereas in the latest edition there are 79. A somewhat rough correspondence with the volume size.
In 1948, following the deaths of both the original authors, the publishers set up an editorial board which would be responsible for future editions. From the earliest days Kaye had recruited NPL staff to help the project, and the association with NPL, and other Government laboratories, has continued. One of the four members of the board, H. Barrell, was a member of the staff of NPL, and one, E.A.Coulson, a member of the staff of the neighbouring Chemical Research Laboratory and my senior officer, which explains how I ultimately became involved. Each board member took responsibility for a part of the book, and found experts in each subject to undertake its revision.
It is obvious from the preface to the 12th edition, written by the chairman Professor N.Feather, that the outcome, the 11th edition (1956), preparation of which had been spread over a long period, was not entirely satisfactory, and they were more satisfied with the 12th (1959). In that, Feather wrote, "Previous users of the tables will recognize that, although in detail much has been altered since the editorial board took over, the essential features of 'Kaye and Laby' remain as before; in particular the 'brief resume containing references', to which feature the first preface already drew attention, is retained as indispensable. And the length of the book is very little different in the twelfth from what it was in the tenth edition; that result in itself has required a considerable effort of self-discipline on the part of editors and contributors."
Today, despite its further increase in size, we can at least say that that self-discipline has been maintained sufficiently for the user still to be able to pick the book up easily with one hand. Successive editions of Kaye and Laby gradually got bigger as knowledge increased; phenomena for which numerical data are significant today, such as the existence of isotopes, were not even known when the first edition appeared. The table of isotopes, appearing on one page in the 7th edition (1932), had increased to five in the 10th (1948). In the preface to the 4th edition (1920) Laby wrote, "The chemical data have been recalculated using the international atomic weights. Some seven hundred additions and alterations in the physical constants of chemical compounds have been made. The published values of these constants have been critically examined and what appear to be the more accurate values for the chemical compounds included in these pages, have been used." This is an excellent summary of what contributors have been doing ever since - critically examining the values of the chosen constants and revising them in the light of current knowledge.
It is interesting to note what has disappeared to make room for the new, and changes in what has been permanent. Not much had gone before the editorial board took over - I have noticed only the disappearance of the recipe for silvering from the 10th edition (1948). In that edition attention to glass reached its peak; there are nearly four pages devoted to the types and properties including composition, annealing characteristics and durability of optical glasses. After 1948 greater changes began. Among them I have noted the following. The table of values of g, the acceleration due to gravity, for about 100 places throughout the world was dropped from the 12th edition (1958) and replaced by an equation relating g to latitude and height. A table of the bursting strengths of glass tubing had also vanished from that edition; perhaps as well because an unknown hand has written against it in the copy of the 3rd edition (1919) that I have used. "These are hopeless" - I hope that such a remark could not be put against any other numbers that have appeared. Emergent stem corrections for mercury thermometers had gone from the 14th edition (1973), as also a table of the properties of fats and waxes. Tables of moments of inertia, tables for the capillary depression of mercury columns, and British Standard Wire Gauge had gone from the 15th edition (1986). Surprisingly to me, the emf of the Weston cell has gone from the 16th edition (1995), but it is nearly 20 years since I was at NPL and was abreast of the latest developments in metrology. However, I do wonder whether all users of Kaye and Laby who need a standard voltage have the equipment to realize the Josephson effect or need state of the art accuracy for their measurements.
That once most thumbed part of any book such as Kaye and Laby, the numerical tables, remained until 14th edition (1973) but had gone in the 15th (1986). This reflects the fact that at some date between 1973 and 1986 pocket calculators that instantly gave more decimal places than could be read from the tables became universal. Some important numbers are still given, but the number of digits causes surprise. Pi and e appeared in 1919 with 9 decimal places and in 1995 with 13 but in the 12th edition (1959) there are only 5, and 5 it remained even until the 15th edition (1986). Curiously, Pi in the form of the Greek letter was put in its normal English alphabetical place in the index in the early editions, but in the 14th edition (1973) it is "Pi" with the Greek letter following in parentheses, and that has continued in subsequent editions.
Some of the tables in the 13th edition (1966) were converted to SI, while some remained in the older units, partly because of the amount of work involved but partly, I suspect, because of the lack of enthusiasm for SI of some of the contributors. One reviewer, J.S.Rowlinson, at least was critical of the mixture of units - was this, perhaps, the only (mildly) adverse review Kaye and Laby has ever received? Reason for that criticism would not be there again, for in the Preface to the 14th edition (1973) the then chairman, A.E.Bailey, was able to state that all tabulated values had been expressed in SI units. But I am glad conversion factors to the old can still be found; the old units have not disappeared from the literature just because they have become obsolete for current use. Degrees Fahrenheit still appear other than as historical curiosities on page 30 of the 16th edition in the definitions relating to hydrometers - will hydrometers still appear in the 17th edition?
One might then wonder. Is there anything unchanged from the beginning? Surely the integral atomic numbers do not need revision? But, of course, we did not have them in 1911 and in the 1st edition the elements (only 81 of them) are arranged in the order of their atomic weights and are given with columns "First isolated by" and "Date", information that is no longer to be found in the book. I think there can be no measured data in Kaye and Laby that have not been changed since its first edition, but we can still find unchanged the dimensions of Whitworth and BA threads, the former still in inches.
I have been a contributor to Kaye and Laby since the 13th edition, for which I prepared a table of vapour-liquid critical properties; in subsequent editions I took over responsibility in addition for the tables of vapour pressures. There will always be a problem with a publication like Kaye and Laby - what to include and what to leave out? Contributors will want to put in that little extra, while the editors are concerned to stop the whole from getting bigger by more, shall we say, than the rate of inflation. In fact, my vapour pressure section has increased by only a small amount since the 13th edition. In that edition the vapour-pressure tables were a selection by my late colleague, E.F.G.Herington, from a 1947 paper by Stull, and in subsequent editions I have made no changes except to add some refrigerants and some compounds having quasi-spherical molecules and also some compounds for which I thought the data were of especially high quality; generally these were ones for which we had made the measurements! Pressures in the 13th edition were in mmHg and for the 14th we had to convert to kPa; fortunately by then we did not have to slog it out with a Brunsviga or Facit or even an electric Diehl or Munroe or Marchant (I wonder for how many readers these names still have meaning; they were mechanical calculators), but were well served at NPL by the KDF9 computer. The values of temperature for the set of tabulated pressures were fitted to a power series from which new temperatures could be calculated for the desired SI pressures. At the same time, if there were more modern and better sources of data these were substituted for those derived from Stull; I have regularly scanned the literature looking for good modern work in the field, and have made use of what other organizations engaged in the same quest offer -equations from the Thermodynamics Research Center at the University of Texas, and also from ESDU International, an organization with which I have been associated that is engaged in surveying the literature and providing recommended values of some physical properties of a wide variety of chemical compounds.
There can be unexpected pitfalls. It was nearly missed that change in the temperature scale in 1968 affected the table giving the variation of the density of mercury with temperature, though it is true that the changes required were of a similar order to that of the probable errors in the values. The table was hastily amended, and has been again to take account of ITS-90. That table is probably a good candidate for omission or truncation next time because equipment that in times gone by used mercury as a pressure transmitting fluid is more likely today to incorporate a diaphragm gauge.
The only challenge I have received about what I have put in has come from other contributors. That is, we have tried to ensure there are no inconsistencies between tables prepared by different contributors, and, happily, no reader has complained to me of a wrong number.
Eighty seven years old, 1911-1998, will Kaye and Laby make its century? It seems to me that there will always be a need for such a compilation, but it also seems an obvious candidate for production in computer readable form. I hope that will not mean the disappearance of the book to take off the shelf and leaf through. I have written this article as a contributor to Kaye and Laby concerned that it should retain its special position among books of reference by being as up to date as possible. A contrasting view is that of Constable, who wrote an article celebrating his delighted acquisition of a first edition. Constable points out how valuable early editions are for historical study because in them are to be found details of the units used at the time, units that in many instances have disappeared from modern reference books.
This article is based on a presentation made by the author at a meeting of the History of Physics Group of the Institute of Physics on 25 April 1998 at the National Physical Laboratory.
Douglas Ambrose was formerly a member of the staff of the Division of Chemical Standards, National Physical Laboratory, and has been a contributor to Kaye and Laby since the 13th edition (1966).
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