DECEMBER I, 1923] NATURE 793 IN mv letter which appeared in NATURE of November A Suggested Modification of " Proton " to 17 I re"ferred to Mr. Arthur Clayden as "the late," "Prouton" as a Memorial to William Prout. when actually he is very much alive. How I came to THE amazing advances in our knowledge of the make this error I cannot understand, but I was most composition and structure of matter achieved during probably thinking of Mr. Clayden as the late Principal the past few decades constitute an important, if not of the University College, Exeter, and so made the quite final, step toward the establishment of the mistake. I much regret the error, an.d shall be essential unity of the physical universe. glad if this correction of it can appear m an early In reviewing the epoch-making work of J. J. issue of NATURE. 'VILLIAM J. S . LocKYER. Thomson, whose electrical theory of matter under• Norman Lockyer Observatory, lies all recent developments in this field, with that of Sidmouth, S. Devon, Rutherford, Ramsay, Soddy, Aston, and others in November 20. England and elsewhere, one should not be unmindful of the contribution made over a century ago by his National Certificates in Chemistry. compatriot, William Prout, an early apostle of unity. I HAVE observed on page 6ro of NATURE for October To all students of chemistry Prout's hypothesis, 27 a reference to the scheme of examinations for published in r8r6, to the effect that all of the elements national certificates in chemistry. are formed from hydrogen by some process of con• The writer of the article, upon the basis of an densation or grouping, has been familiar by reason of expression of opinion commencing with the word the stimulus it has afforded to accurate experimental " apparently," proceeds to criticise something o.n work. Relegated for many years to the limbo of which he is not fully informed. The sch:eme discarded theories, it has at last emerged to increased " designed to secure all the advantages of plausibility. Although of necessity less specific than examinations and of reasonable freedom m the the hydrogen-helium theory of Harkins, it is corre• arrangement of the courses of work to meet local spondingly simpler, and equally valid if the helium conditions and needs," and the writer need ndt fear atom, with its four protons and four electrons, be that there is any truth in the suggestion that before regarded as an intra-atomic polymeride or condensa• courses of study are recognised th.ey are modified or tion product of hydrogen. However intricately the mutilated by the Board of Education. more densely populated' communities of protons and So far as national certificates in chemistry and the electrons may be arranged in the heavier atoms, the courses leading thereto are concer?-ed, the acts one proton and one electron of the atom of hydrogen only in conjunction with the Institute of certainly constitute the " first pair" in the chemical The experience of the first two exammabons for Garden of Eden, or present the first stage in the such certificates has amply demonstrated the upward evolution of the elements. ness of the scheme. No complaint of bureaucratic In recognition of the genius and insight of William intervention has been submitted either to the Board Prout it is suggested herewith that the name" proton" or to the Institute. recently assigned to the unit charge of positive elec• So far from insisting on " that machine-like uni• tricity, be modified, with some small sacrifice of formity beloved by bureaucrats," the examination etymological accuracy, to "prouton," a term with papers have, in fact, been set either by the local distinctive historical connotation. schools or by their own affiliated groups-such as the ARTHUR WESLEY BROWNE. Union of Lancashire and Cheshire Institutes. Cornell University, The view of the writer as to the need of "some Ithaca, N.Y., U.S.A. measure of central control and to some sound and official organisation " is incontestable : ·those siderata are precisely those which the scheme 1s An Uncommon Type of Cloud. designed to attain. RICHARD B. PILCHER, IN NATURE of November 17, p. 725, Dr. Lockyer Registrar and Secretary. puts forward a suggestion as to the physics of the Institute of Chemistry, formation of "mammato-cumulus" cloud, namely, 30 Russell Square, London, W.C.r, that it is formed by descent of moist air into colder air November 13. below, when there is a reversed vertical temperature gradient, in the same way that " cumulus " clouds MR. PILCHER will know that before an educational are formed by an ascent of warm air (when there is institution can submit candidates for national certifi• a normal temperature gradient) into colder air above. cates the course of study proposed must be approved Any satisfactory explanation of the formation of by the Board. This, of course, is absolutely this type of cloud would be welcome, but surely and desirable but it is at this stage that modificatiOns " cumulus " clouds are formed by · the adiabatic may be by the Board-the alterna!ive to cooling when moist air rises to a place where the acceptance being refusal to place the mstitutwn atmospheric pressure is lower. The general decrease. concerned on the approved list. I do not suppose for of temperature upwards is only necessary to make one moment that modifications of courses proposed such ascent of air possible. A descent of air, such are not necessary I?ut I do as Dr. Lockyer suggests, must be accompanied by the trend of the modificatiOns IS towards umform1ty adiabatic warming, since the pressure is increased of syllabuses. whatever. the general vertical temperature gradient I have no suggestions to make, at present, on the may be. It is true that some cloud might be formed actual conduct of the examinations, and I know that by the mixing which might occur at the surface the papers are set by the local schools and assessed of separation between two ·masses of nearly saturated by gentlemen whose work is not questioned .. air at different temperatures, but this would not be reference was made distinctly to the pre-recogmhon expected to form the dense globules of cloud actually stage, and I can assure Mr. Pilcher that I did not seen with this type of cloud formation. write without some knowledge. I would also point out that I was referring to G. M. B. DoBSON. complete courses of work-including Robinwood, Boar's Hill, Oxford, to the main subject, and covenng a penod of from three November 17. to five years. THE WRITER OF THE ARTICLE. NO. 2822, VOL. I I 2 J Y2 © 1923 Nature Publishing Group