bluuebunny/crossref_metadata_2025 huggingface dataset:
The rate of transformation to methylurea of methylammonium cyanate dissolved in ethyl alcohol
Authors: Miller Christina Cruickshank
Published: December 2006

A year ago I showed that the production of methylurea from methyl-ammonium cyanate, in aqueous solution, may be due to the interaction of methylammonium and cyanate ions in a reversible bimolecular reaction, the velocity
v
of which, if the reverse reaction be ignored, is given by the equation,
v
=
k
C
a
C
b
F.
k
is the velocity constant, C
a
and C
b
are the concentrations of the reactants, based on the assumption that dissociation into ions is complete, and F is a reaction kinetic factor, probably
f
a
f
b
/
f
x
as defined by Brönsted;
f
a
,
f
b
, and
f
x
represent, respectively, the activity coefficients of the reactants and a critical complex X. For an infinitely dilute solution the velocity constant derived theoretically, with the aid of an approximate form of Christiansen’s equation for a bi-molecular reaction of measurable velocity between univalent ions of opposite sign, was in excellent agreement with that obtained by extrapolation from the experimental data. Ammonium cyanate seemed to conform also to the theory. It was proposed to extend the investigation to ethyl alcoholic solutions of methylammonium cyanate, for which no data were available. Walker and Kay, and Ross found that ammonium cyanate was transformed at a much greater rate in alcoholic solutions, but their data refer to one temperature only, with the result that the applicability of Christiansen’s equation cannot be tested, and no definite conclusion regarding the solvent effect can be drawn.
The nature of cosmic rays
Authors: Clay Janet
Published: December 2006

1—When Bothe and Kolhörster in 1929 first put forward the idea that the ultra-radiation might be of a corpuscular nature, on evidence derived from their counter experiments, it was not proved that the
primary
rays were corpuscular. At that time it was still difficult to accept that corpuscles could have the high energies which were necessary to enable them to penetrate the atmosphere. But also there were two other objections: if the primary rays were corpuscular, the earth's magnetic field should have an influence on their distribution and this was denied by Millikan; also Bothe and Kolhörster, as well as others, did not find a latitude variation. The only exception was given by the results of the writer (1927, 1928, 1929), which did not carry absolute conviction. Also Regener and Millikan had found their absorption curves in water, which had a great similarity to photon-absorption curves, and, moreover, Millikan had based on these far-reaching and interesting consequences about the origin of the rays.2—When, however, in 1932 a new expedition of Clay and Berlage confirmed the former results and at the same time the world survey of Compton led to the same conclusion, it could no longer be denied that
part
of the primary radiation must be corpuscular. After tht new measurements of Hoerlin, Prins, Auger and Leprince-Ringues, Millikan, and the Dutch Cosmic Ray Expedition of 1933 have made this certain.
Specific heat of a supraconducting alloy
Authors: Mendelssohn K. , Moore James R.
Published: December 2006

In a previous note Keeley, Mendelssohn and Moore have shown that the magnetic behaviour of supraconducting alloys differs considerably from that of pure metals. This led to investigations on other properties of supraconducting alloys to discover if this difference was due to a fundamental difference in the nature of supraconductivity in pure metals and in alloys. Experiments have therefore been carried out on the energy content of a supraconducting alloy. Keesom and his collaborators have found a discontinuity in the specific heats of pure metals at the temperature at which they become supraconducting. The magnitude of this discontinuity has been correlated with the steepness of the magnetic threshold curve at the transition point by a simple formula due to Rutgers.
Optically Active Di- and Tetra-methyl-spiro-5 : 5-Dihydantoins
Authors: Pope William Jackson , Whiteworth James Bell
Published: December 2006

In a previous paper* we described the resolution into optically active components of the
spiro
-5: 5-dihydantoin 7 6 1 2 NH—CO—C—NH—CO ∣ ∣ CO—NH—C— CO-NH 8 9 4 3 prepared by Biltz, Heyn, and Bergius; these compounds are probably the simplest optically active spiranes which can be obtained and may therefore be regarded as the type case of optical activity associated with one particular kind of molecular configuration. We also adduced evidence, based on the different rotatory dispersions shown by the optically active dihydantoins in absence and presence of alkali, indicating that these substances could assume three tautomeric forms. This work has now been extended to the study of the optically active 3: 7-dimethyl-
spiro
-5: 5-dihydantoins and their acidyl derivatives and tetramethyl-
spiro
-5: 5-dihydantoins. Tetramethyldihydantoin, which can only exist in the ketonic state, gives, in methyl alcohol, a rotatory dis-persion curve of the simple form, with λ
0
= 2478 A, nearly congruent with that of the unsubstituted dihydantoin in alcoholic solution with λ
0
= 2453 A. This is a further indication that in neutral solvents and pyridine the dihydantoin has the ketonic form. The 3: 7-dimethyl- dihydantoin also shows normal rotatory dispersion in methyl alcohol and the curve, with λ
0
= 2381 A, is nearly congruent with those just quoted; it should therefore be of the ketonic form in neutral solvents. The initial rotatory power of this compound in dilute soda solution is only about one-seventh of that in alcohol; passage to a tautomeric enolic form is thus indicated. The specific rotatory power in soda solution rapidly falls, however, to —1-6° for λ = 5461, a value which persists for some time; the falling off in rotatory power is due to hydrolysis with formation of 3: 8-dimethylallantoin, CH3 . NH . CO . NH . CH—NH . CO ∣ CO . N . CH
3
Although this compound was only isolated from the soda solution in an optically inactive form, it would seem to exist in the optically active form in the cold soda solution. This result is of interest in connexion with recent work on the optical activity of allantoin itself.*
The tidal oscillation in an elliptic basin of variable depth-II
Authors: Goldsbrough George Ridsdale
Published: December 2006

The problem of the long waves in an elliptic lake with a paraboloidal law of depth was solved in a previous paper.* It appeared that the solutions could be expressed in terms of certain algebraic polynomials, from whose general properties the character of the motions could be readily derived. The subject of the present paper is the more important problem of the same basin subjected to rotation. The analogous problem of a rotating elliptic lake of uniform depth has been solved by Goldstein who used infinite series of elliptic cylinder functions. The law of depth used in the present paper, however, enables the solutions to be expressed in terms of finite sets of polynomials. The earlier modes can be completely determined without recourse to long arithmetical calculation and the interpretation of the analysis is easier. In the course of the work many properties of the polynomial are investigated.
The crystal structure of pentaerythritol tetracetate.
Authors: Goodwin T. H. , Hardy R.
Published: December 2006

Although the technique for investigating organic crystals by X-rays is now fairly well developed, there are still many important types of compound of which no representative has yet been examined. In particular no Fourier analysis of an ester has ever been published and no reliable information is available as to the lengths of C—O and C=O bonds in such substances. The investigation of pentaerythritol tetracetate recorded here was made partly to supply this deficiency and partly to develop the study of pentaerythritol (Llewellyn, Cox and Goodwin 1937). A further incentive lay in the doubt which existed at one time regarding the distribution of the valencies of the central carbon atom in the tetracetate; this is discussed in § III. The results of the investigation are presented at once, the methods by which they were deduced being described in the last section.
X-ray analysis of the dibenzyl series V-Tolane and the triple bond.
Authors: Robertson John Monteath , Woodward Ida
Published: December 2006

The detailed structure of stilbene has recently been described (Robertson and Woodward 1937) and a theoretical discussion of the resonance problem in that type of molecule is now given by Penney and Kynch (1938). The crystal symmetry and dimensions of a number of compounds are closely similar to those of stilbene, and it is possible to make use of this isomorphism to carry out a very direct analysis of these other structures. In X-ray analysis it is generally necessary in the first place to assume some model for the structure and then adjust the parameters by a process of trial and error until a fair measure of agreement is obtained between the calculated and the observed values of the structure amplitudes. Subsequent refinement of the parameter values can then be attained by the application of Fourier series methods. With an isomorphous series of the present kind, however, when the structure of one member has been accurately determined, it is often possible to eliminate the first and most laborious part of the analysis for the other members, and proceed to the solution directly by the successive application of Fourier series methods.
On the velocity and temperature distributions in the turbulent wake behind a heated body of revolution.
Authors: Tomotika S.
Published: December 2006

1. The calculation of the distribution of mean velocity in the turbulent wake behind a body of revolution in a uniform stream of an incompressible fluid was first carried out by Swain (1929) by using Prandtl’s momentum transport theory of turbulent motion. The uniform stream was considered to be parallel to the axis of revolution of the body and the mean motion was assumed to be symmetrical about the same axis. Swain further adopted Prandtl’s assumptions that for sufficiently high Reynolds numbers and at a sufficient distance downstream, there is geometrical and mechanical similarity in different sections of the wake, and that the values of the mixing length,
l
, at corresponding points in different sections are proportional to the breadths of the sections. She also assumed, as done by Schlichting (1930) in his discussion of the two-dimensional wind-shadow problem, that the mixing length
l
is constant over any one section of the wake. Now, taking the
x
-axis along the axis of revolution of the body and the
r
-axis perpendicular to it, let the undisturbed velocity be denoted by
U
. Then, the
x
-component of velocity
u
, in the wake may be written as
u = U - u
. (1) Swain’s analysis shows that the distribution of
u
for the first approximation may be expressed in the form
u/u
0
= ( l - ξ
1/2
!)2. where
u
0
is the value of
u
at the centre of the wake in any given section and ξ =
r/r
0
,
r
0
being the value of
r
at the edge of the wake.
Application of the modified vorticity transport theory to the turbulent spreading of a jet of air.
Authors: Tomotika S.
Published: December 2006

1. The turbulent spreading of a jet of air emerging from a small circular aperture has been discussed by Tollmien (1926) on the basis of Prandtl’s momentum transport theory of turbulence, by making some appropriate assumptions. He has calculated the distribution of mean velocity in the jet at distances which are sufficiently great compared with the diameter of the aperture and it has been found that the calculated distribution of mean axial velocity is in satisfactorily good agreement with observations made at Göttingen. The same problem seems to have been discussed also by L. Howarth in an unpublished paper on the basis of Taylor’s vorticity transport theory of turbulence, by assuming that not only the mean motion, but also the turbulent motion, is symmetrical about the axis of a jet. It appears, how­ever, that the agreement between Howarth’s results of calculations and the Göttingen measurements is not so good as in the case of Tollmien’s results of calculations on the momentum transport theory.
Comparison of wave-functions for HeH
++
and HeH
+
Authors: Coulson Charles Alfred , Duncanson W. E.
Published: December 2006

Before trustworthy predictions can be made concerning the reliability of various approximate wave-functions in the case of complicated molecules, it is necessary to study the simplest molecules in as great detail as possible. Such a study enables one to assess the merits and inaccuracies of the different approximations in a way that is impossible with the more complex systems. The simplest of all molecular problems is H
+
2
, and this ion has been studied thoroughly by several writers (e.g. Dickinson 1933; Sandemann I935; Steensholt 1936
a, b
). The simplest two-electron problem is that of H
2
, and a very complete knowledge of the wave-functions for this molecule has been obtained (e.g. Weinbaum 1933; Coolidge and James 1933; Coulson 1937
a
). In order of increasing complexity the next molecule is the two-electron ion H
3
+
, which has been discussed by Coulson (1935), by Eyring, Rosen and Hirschfelder (1936) and Hirschfelder, Diamond and Eyring (1937). All these molecules are homonuclear, however, so that the binding is predominantly covalent; but the majority of molecules experimentally observed are heteropolar, and then the binding is largely ionic. The present paper, therefore, extends the calculations already made for H
+
2
, H
2
and H
+
3
, and discusses in detail the two simplest heteronuclear molecules, viz. the ground states of the single-electron ion HeH
++
and of the double-electron ion HeH
+
. The object of the paper is primarily to compare the different types of wave-functions, and for this purpose as many diverse methods as possible have been employed; it is not important, from this point of view, that the HeH
++
ion is unstable and that the HeH
+
ion is stable. This work may be regarded as the analogue, in the molecular sphere, of a recent paper by Baber and Hassé (1937) on He, in the atomic sphere. Some of the methods used for the single-electron bond have no immediate counterpart in the discussion of the two-electron bond, and accordingly the two problems are treated independently.
The production of gamma-rays by neutrons
Authors: Burhop Eric Henry Stonely , Hill R. D. , Townsend Albert Alan
Published: December 2006

The production of
γ
-radiation due to the passage of neutrons through matter was discovered by Lea (1935) and has been subsequently investigated by a number of workers. The experiments of Lea with fast neutrons appeared to indicate that the
γ
-radiation arises from a process of inelastic scattering of neutrons. Evidence for the occurrence of inelastic scattering of fast neutrons has been obtained by Danysz and others (1934) and Ehrenberg (1935) and it has been pointed out by Bohr that on current theories of the interaction between fast neutrons and atomic nuclei most of the scattering would be expected to be inelastic. On the other hand, measurements of the absorption of slow neutrons in elements which emit
γ
-rays (e. g. Cd, Hg) show that the absorption is a sharp resonance process, and it is assumed that the
γ
-radiation in these cases arises from neutron capture. The present work was undertaken with a view to determining the energies of the neutrons which give rise to the
γ
-radiation, in an attempt to throw some light on the mechanism of its production.
Oscillography of adsorption phenomena III. Rates of deposition of oxygen upon tungsten
Authors: Johnson M. C. , Henson A. F.
Published: December 2006

The only temperature coefficient hitherto measured for the atomic layer of oxygen on tungsten is that which demonstrates the 150,000 cal. /mol. expended in its desorption. If, however, some energy is required before the difference between this heat of adsorption and the heat of dissociation can be liberated, a further temperature coefficient will exist, giving variability to the “condensation coefficient” or fraction of impinging molecules which become enabled to contribute to this layer. Any such variability extends the notion of “activated adsorption” from the slow processes with which it has become associated to the almost instantaneous reaction of “chemisorption”. Since filling of the atomic layer is generally supposed to precede oxidation, and oxidation itself has already been studied through the subsequent volatilization of oxide (Langmuir 1915; Rideal and Wans-brough-Jones 1929), an experimental determination of whether the initial deposition also needs activating would be highly desirable. This would, however, be inaccessible to most technique because of the high speed of recording needed. The oscillographic study of reaction velocity, developed by one of us in collaboration with Dr F. A. Vick, and hitherto applied only to evaporation (Johnson and Vick 1935), offers the opportunity by suitable modifications. It fulfills the following requirements. (1) Reaction time may be kept below 1 sec., avoiding the usual slow contaminations due to gases which strike the walls. (2) The surface may be proved to be clean, within a second of gas being admitted, by observation of its thermionic emission, thus escaping the common ascription of activations to impurity. (3) The gas-covered fraction may be kept small enough to avoid interaction between surface particles. (4) No other substance beside oxygen and tungsten is introduced as reagent or as indicator.
On the motion of a fluid heated from below
Authors: Schmidt R. J. , Saunders O. A.
Published: December 2006

In some previous experiments (Schmidt and Milverton 1935) a layer of water between two horizontal plates was slowly heated from below. The critical temperature difference at which the water began to move was found from a change in the slope of the curve relating the difference of temperature between the plates and the rate of supply of heat to the lower plate. An optical refraction (Saunders and Fishenden 1935) method was also used for finding the critical condition, and the results found by the two methods agreed and conformed to a theoretical formula of Jeffreys (1928) within the limits of experimental error. The present experiments were undertaken to find whether any change in the type of motion occurs at higher temperature differences, and also to study further the vertical and horizontal temperature gradients in the moving fluid using the optical method. It was also thought of interest to perform experiments with air instead of water. An improved apparatus was used, in which the downward heat loss from the lower plate could be measured, so that the actual heat transfer between the plates could be found.
On the neutrino theory of light
Authors: Pryce Maurice Henry Lecorney
Published: December 2006

The neutrino theory of light, developed by Jordan, Kronig and others, is based on an idea of de Broglie’s, who suggested that one should regard a photon, not as a simple system, but as composed of two elementary particles bound together in some way (de Broglie 1932, 1933, 1934). According to de Broglie these particles are to be regarded as complementary in the same sense as electrons and positrons are complementary. This idea gives a good account of the creation and annihilation of photons and allows them to obey the Bose-Einstein statistics while retaining the idea that all elementary particles obey the Fermi-Dirac statistics and possess spin angular momentum ½
ħ
. As developed by de Broglie, however, the hypothesis led to the consequence that the component particles each had exactly equal energy and momentum; thus if the state of the photon is known the state of the components can be inferred. The fact that, although the representatives are symmetrical with respect to interchange of two photons, it is then nevertheless impossible for two photons to be in the same state, owing to the underlying Fermi-Dirac statistics of the components, and so the photons would to all intents and purposes themselves obey the Fermi-Dirac statistics, led Jordan to modify the hypothesis (Jordan 1935). He suggested that it is not the interaction between the neutrinos and antineutrinos that binds them together into photons, but rather
the manner in which they interact with charged particles that leads to the simplified description of light in terms of photons
. To account for the process usually interpreted as the emission of a photon of circular frequency
ω
from an atom, he proposed that one of the following two processes can occur:
A suggestion for unifying quantum theory and relativity
Authors: Born Max
Published: December 2006

There seems to be a general conviction that the difficulties of our present theory of ultimate particles and nuclear phenomena (the infinite values of the self energy, the zero energy and other quantities) are connected with the problem of merging quantum theory and relativity into a consistent unit. Eddington’s book, “Relativity of the Proton and the Electron”, is an expression of this tendency; but his attempt to link the properties of the smallest particles to those of the whole universe contradicts strongly my physical intuition. Therefore I have considered the question whether there may exist other possibilities of unifying quantum theory and the principle of general invariance, which seems to me the essential thing, as gravitation by its order of magnitude is a molar effect and applies only to masses in bulk, not to the ultimate particles. I present here an idea which seems to be attractive by its simplicity and may lead to a satisfactory theory. 1. Reciprocity The Motion of a free particle in quantum theory is represented by a plane wave
A exp
[
i
/ℏ
p

k

x

k

], where
x
1
,
x
2
,
x
3
,
x
4
are the co-ordinates of space-time
x
,
y
,
z
,
ct
, and
p
1
,
p
2
,
p
3
,
p
4
the components of momentum-energy
p

x

,
p

y

,
p

z

,
E
. The expression is completely symmetric in the two 4-vectors
x
and
p
. The transformation theory of quantum mechanics extends this “reciprocity” systematically. In a representation of the operators
x

k

,
p

k

in the Hilbert space for which the
x

k

are diagonal (
δ
-funcions), the
p

k

are given by ℏ/
i
∂/∂
x

k

; and vice versa, if the
p

k

are diagonal the
x

k

are given by ­­­­—ℏ/
i
∂/∂
p

k

. Any wave equation in the
x
-space can be transformed into another equation in the
p
-space, by help of the transformation φ(
p
) = ∫
ψ
(
x
) exp [
i
/ℏ
p

k

x

k

]
dx
.
Resolution and interpretation of the luminescent spectra of some solids at low temperatures
Authors: Ewles J.
Published: December 2006

Luminescent inorganic solids may be divided into a number of classes. Some, like the uranyl salts and rare earth salts, show luminescence in the pure state, and some, like the Lenard and Klatt sulphides, seem to require a Small trace of impurity. The alkali halides, which may be rendered luminescent by prolonged heating in the vapour of the alkali metal, by electrolysis, or by exposure to short waves, may possibly be regarded as belonging to the second class, since it its generally recognized that the luminescence is connected with the presence of neutral atoms which must be considered as impurities in the ionic lattice. The chromium-activated substances studied so extensively by Deutschbein (1932) appear to belong to a third class. The intimate relations which have been found between the line-like emission and absorption spectra of the first class suggests that their luminescence may be quite simply explained as a kind of resonance phenomenon. Indeed, in the case of the rare earths the spectra appear to have been satisfactorily interpreted in terms of electronic transitions of the metallic ion. But, in spite of the very large amount of work on the second class of luminescent substances, a satisfactory explanation of their luminescence is still lacking. This is chiefly due to the fact that their spectra generally consist of broad and featureless bands. Various workers have claimed to have resolved these very broad bands into a number of partial bands, and Schmidt (1932) and Schellenberg (1932) have attempted to establish general series relationships among the partial band maxima. The resolution, however, has been obtained partly by visual observations and partly by reconstruction of the broad bands from a number of assumed partial bands. Howes (1928) obtained by visual spectrophotometry distinct structure in the bands of some of the alkali earth sulphides. His results will be referred to later in this paper. Tanaka (1921) carried out an extensive series of observations on the cathodo-luminescence of a large number of substances activated by various impurities and deduced the existence of a frequency interval characteristic of the activator. But as many of his numbers are the result or rearranging the slight fluctuations which appear on the visually observed spectrophotometric curves, the validity of his deductions is very doubtful.
The two-stage auto-ignition of hydrocarbons and "knock"
Authors: Kane G. P.
Published: December 2006

The investigations of Townend and co-workers (1934) have revealed that the spontaneous ignition of higher paraffins in admixture with air consists in certain temperature ranges usually between 270 and 400°C., of a two-stage process, preceded by a time intervalt1prior to the appearance of a cool flame, and a subsequent intervalt2before the occurrence of normal ignition. The reactions involved may be indicated as proceeding fromA→B→C, WhereBdenotes the rapid formation of intermediate products by the passage of a cool flame. Above and below this temperature range the ignitions are no longer composite and after a time intervaltappear to result directly from the processA→C. Apart from their intrinsic interest, these results have a practical bearing on the problem of "knock" in internal combustion engines. For, whereas the minimum pressures for ignition in the cool flame region of the paraffins and olefins containing more than three carbon atoms have been shown to be related to their knocking propensities in engine practice, non-knocking fuels such as methane have failed to reveal any cool flame systems at all, even at pressures up to 30 atm. While the precise mechanism of "knock" is as yet not entirely understood, it is generally recognized that the phenomenon arises as the outcome of the passage of an explosion flame through a fuel-air mixture which has attained a state of enhanced chemical reactivity (cf. Egerton and co-authors 1938).
On the function of flowers
Authors: Bell Graham , Hamilton William Donald
Published: December 2006

Most flowers are bisexual in function, but counting secondary allocation to attractive structures such as the corolla as equally male and female leads to the paradoxical conclusion that plants bearing perfect flowers invariably allocate much more to female than to male function. A method of calculating the gender of secondary floral allocation is described, and it is speculated that this allocation is predominantly male. Observations and experiments with natural populations of herbs, designed to test this hypothesis gave the following major results, (i) Insects visit larger flowers more frequently (
Fragaria
), and removal of floral biomass causes a reduction in the frequency of insect visits proportional to the fraction of biomass removed (
Impatiens
). (ii) Removal of attractive structures may cause a decline in the probability that a fruit will be formed but has no effect on the number of seeds set per fruit; thus, mutilation of essentially solitary flowers has no effect on seed-set per fruit (
Impatiens
), while removal of flowers from inflorescences in a species that forms several many-seeded fruits per inflorescence reduces fruit-set per inflorescence but has no effect on seed-set per fruit (
Asclepias
), and removal of sterile flowers from an inflorescence in which the fertile flowers yield one-seeded fruits is effective in reducing seed-set per inflorescence (
Viburnum
), (iii) Larger flowers may disperse a greater fraction of their pollen in unit time (
Impatiens
) and the removal of flowers from inflorescences causes a steep reduction in total pollen exported and a weak decline in the quantity of pollen exported per flower (
Asclepias
). These results are consistent with the hypothesis that a single insect visit (or a very few visits) suffices to fertilize almost all available ovules and is procured by a very small allocation to attractive structures, while much greater allocation is necessary to procure the numerous visits required to disperse a large fraction of the pollen. This inference is supported by a comparative survey of sexually dimorphic plants, in which male flowers are generally larger than female flowers, male inflorescences bear more flowers, and male plants bear more inflorescences. It is concluded that the flower is primarily a male organ, in the sense that the bulk of allocation to secondary floral structures is designed to procure the export of pollen rather than the fertilization of ovules. This conclusion may be sensitive to whether it is the flower or the inflorescence as a whole that represents the primary unit of attraction to insects. It was found that the performance of a given flower was substantially affected by other flowers in the same compact inflorescence (
Asclepias
), though not by other inflorescences on the same plant nor by those borne by nearby plants (
Fragaria, Impatiens
). A general quantitative theory of flower and inflorescence design is outlined, and used to organize the extensive experimental results for
Asclepias
.
Songbird migration across the Sahara: the non-stop hypothesis rejected!
Authors: Schmaljohann Heiko , Liechti Felix , Bruderer Bruno
Published: December 2006

Billions of songbirds breeding in the Western Palaearctic cross the largest desert of the world, the Sahara, twice a year. While crossing Europe, the vast majority use an intermittent flight strategy, i.e. fly at night and rest or feed during the day. However, it was long assumed that they overcome the Sahara in a 40 h non-stop flight. In this study, we observed bird migration with radar in the plain sand desert of the Western Sahara (Mauritania) during autumn and spring migration and revealed a clear prevalence of intermittent migration. Massive departures of songbirds just after sunset independent of site and season suggests strongly that songbirds spent the day in the plain desert. Thus, most songbirds cross the Sahara predominately by the intermittent flight strategy. Autumn migration took place mainly at low altitudes with high temperatures, its density decreased abruptly before sunrise, followed by very little daytime migration. Migration was highly restricted to night-time and matched perfectly the intermittent flight strategy. However, in spring, when migratory flights occurred at much higher altitudes than in autumn, in cool air, about 17% of the songbird migration occurred during the day. This suggests that flying in high temperatures and turbulent air, as is the case in autumn, may lead to an increase in water and/or energy loss and may prevent songbirds from prolonged flights into the day.
On the acoustic shadow of a sphere. With an Appendix, giving the values of Legendre's functions from P
0
to P
20
at intervals of five degrees.
Authors: Strutt John William , Lodge A.
Published: December 2006

The problem here considered is that of the intensity of sound at the various points of a rigid and fixed sphere on which plane waves impinge, or reciprocally the intensity at a distance in various directions due to a source of sound situate upon the surface of the sphere. The analytical solution is readily given, but in the interpretation everything depends upon the ratio of the wave-length (2
π
/
k
) to the circumference (2
πc
). If
kc
be small, the sphere has little effect. In my book on the “Theory of Sound,” 328, I have considered (but only for certain special directions) the case of
kc
= 2. The extension to various directions is now given; and the calculation is pushed to the case of
kc
= 10, about as far as is practicable. For this purpose the values of Legendre’s Functions up to P
20
are required.
A new method of detecting electrical oscillations.
Authors: Ewing James Alfred , Walter L. H.
Published: December 2006

The magnetic detector of Rutherford, though now well known, appears to have created little interest until attention was directed to the subject by Marconi’s adaptation of the method to his telephonic detector. Marconi’s apparatus employs the change of hysteresis, which is produced in iron by the influence of electric oscillations, when these are caused to pass through a coil surrounding the iron, the change being made manifest by means of a telephone. In his view, the electric oscillations act by reducing the hysteresis. It occurred to us to exhibit the alteration in hysteresis by a different method, namely, by applying the principle which is used in an instrument invented some years ago by one of us for the mechanical measurement of hysteresis. In that instrument! the hysteresis is measured by the mechanical couple between a magnetic field and the iron, when either the iron or the magnet providing the field is caused to revolve. Thus, if the field revolves, the iron tends to be dragged after it, as a consequence of hysteresis in the reversals of its magnetism, and if the motion is prevented by a spring or other control, it assumes a deflected position. Suppose, now, the electric oscillations to act on it, any change of the hysteresis caused by them will be exhibited by a corresponding change in the deflection. We anticipated, in accordance with the generally accepted view that hysteresis is reduced by the oscillations, that their presence would be detected by a fall in the deflection.
A contribution to the study of the action of Indian cobra poison.
Authors: Elliot R. H. , Fraser Thomas Richard
Published: December 2006

Brunton and Fayrerf discussed the pharmacology of Cobra venom at some length; they attributed the effects of the poison to its action on the cerebro-spinal nerve-centres, especially on the respiratory centre. They observed that Cobra venom had a direct action on cardiac muscle, and that it also affected the heart through the vagal system, but they did not lay much stress on circulatory failure.
The optical properties of vitreous silica.
Authors: Gifford J. William , Shenstone William Ashwell
Published: December 2006

The properties of vitreous silica suggest that it is not unlikely to play an important part in optical work. Its composition is definite, that is to say, it is not liable to those minute variations which make it impossible, we believe, to produce with certainty two meltings of glass which exhibit no sensible difference in their optical properties when tested by a first-rate spectrometer.
The specific heats of metals and the relation of specif heat to atomic weight.—Part III.
Authors: Tilden William Augustus
Published: December 2006

The object of the experiments, of which an account is given in thi paper, was to determine whether the atomic heats of the element entering into combination are preserved in the compound at al temperatures, previous results obtained by the author and other having shown that the specific heats of metals of small atomic weight such as aluminium, increase very rapidly with rise of temperature.
Some uses of cylindrical lens-systems, including rotation of images.
Authors: Burch George James
Published: December 2006

It was, I believe, first shown by the late Sir George Stokes that if two similar cylindrical lenses are placed in contact, with their axes of curvature at right angles, the combination acts as a spherical lens, and that if the axes are not at right angles the system is equivalent to a cylindrical and a spherical lens combined, the spherical element dis­appearing when the axes are parallel.
Corrigenda in Mr. W. Shanks's Tables ‘on the number of figures in the reciprocal of a prime’.
Authors: Cunningham Allan
Published: December 2006

This paper contains the result of an examination of the late Mr. W. Shanks’s MS. Tables, with above title, now deposited with the Royal Society. These tables have been
collated
with the following printed Tables.
The general theory of integration.
Authors: Young William Henry , Hobson Ernest William
Published: December 2006

The paper begins with a recapitulation of the well-known definitions of integration and of upper and lower integration (intégral par excès, par défant ; oberes, unteres Integral). The theorem on which the Darboux definition of upper (lower) integration is founded is stated and proved in the following form :— Given any small positive quantity
e
1
, we can determine a positive quantity
e
, such that, if the fundamental segment S be divided up in any manner into a finite number of intervals, then, provided only the length of each interval is less than
e
, the upper summa­tion of any function over these intervals differs by less than
e
1
from a definite limiting value (the upper integral).
Fatigue in aerostructures—where structural health monitoring can contribute to a complex subject
Authors: Boller Christian , Buderath Matthias
Published: December 2006

An overview of the aircraft design and maintenance process is given with specific emphasis on the fatigue design as well as the phenomenon of the ageing aircraft observed over the life cycle. The different measures taken to guarantee structural integrity along the maintenance process are addressed. The impact of structural health monitoring as a means of possibly revolutionizing the current aircraft structural monitoring and design process is emphasized and comparison is made to jet engines and helicopters, where health monitoring has already found the respective breakthrough.
An account of the observations, made by the Philosophical Academy at Paris, May 12 1667. about 9. of the clock in the morning, of an Halo or circle about the Sun; together with a discourse of M. Hugens de Zulechem, concerning the cause of these meteors, as also that of Parelia's or Mock-suns. Englished out of French by the Publisher, to whom it was sent but lately from the worth author of the said discourse
Authors: de Zulichem Hugens
Published: December 2006

The Diameter of this Circle, which was exactly observ'd, was found to be of 44 degrees, and the breadth of the Limb thereof, of about half a degree.
Some observations, directions and inquiries concerning the motion of sap in trees, in pursuance of what was formerly begun therein, about the letter end of 1668. and the next following spring, by Dr Ezerel Tonge, and Francis Willoughby Esq;
Authors: Tonge Ezerel , Willoughby Francis
Published: December 2006

I Now begin my Inquiries and remarks upon the last publisht Observations of those Ingenious persons Mr
Willoughby
and Mr
Wray
in your
Pb
.
Transact
. N. 48.
An accompt given by a Florentin Patrician, call'd Jo. Battista Donius, concerning a way of restoring the salubrity of the country about Rome: extracted out of the ninth Italian giornale de letterati; and English't as follows
Authors: Donius Jo. Battista
Published: December 2006

The Campagne of
Rome
, (which is that Tract of Land, that is destitute of Inhabitants and Trees, and extends it self for many miles, taking in
Latium
, and part of the antient
Sabins
, and of
Tuscany
,) would be of great use to the State, and of subsistence to the people, if it could be Inhabited without that great danger to health, which now tis so much noted and fear’d for;
Some communication, confirming the present appearance of the ring about Saturn, by M. Hugens de Zulechem and Mr. Hook
Authors: De Zulechem M. Hugens , Hooke Robert
Published: December 2006

The former writeth in a letter of his, dated at the Hague Octob. 31. 1670. st. n.
A certain phænomenon, seen by Monsieur Hevelius, Feb. 5. 1674. st. no. not far from Marienburgh in Borussia, about the sun, a little before his setting and the moons conjunction, and the suns eclipse, (which yet was not seen by him.)
Authors: Hevelius Johannes
Published: December 2006

I Saw at that time (
saith the Observer
) the Sun, in a sky every where serene enough, being yet some degrees above the Horizon, and shining very bright, yet lancing out very long and reddish rays, 40 or 50 degrees toward the Zenith (as appears
Fig
. 3.)
An extract of a letter of Monsieur Hevelius, lately written to the publisher, together with the copy of a letter of Dr. Wasmuth, giving a large account of a new Astronomico-Chronological work, now by him preparing. Both deli­ver’d in the same language, wherein they were written
Authors: Hevelius Johannes , Wasmuth
Published: December 2006

Præterea cùm nihil hac vice relatu dignum occurrat, quod vobis communicare possim
;
Observations concerning the Comet was seen in Brasil A. 1668. in March by P. Valentin Estance a Jesuite and by him sent to Rome; where they were printed in the 9th Italian Giornale de Letterati, Septemb. 31. 1673
Authors: Estance P. Valentin
Published: December 2006

This being the same Comet with that, taken notice of in
Numb
. 35. of these Tracts, and our account, then given of the same, being likely to receive some advantage and light from these Observations, made in
Brasil
, and but lately come to our hands, we thought it would not be un-acceptable to the Curious in
England
, to see them English’t out of the
Italian
, and here inserted.
Microscopical observations from Leeuwenhoeck, concerning blood, milk, bones, the brain, spitle, and cuticula, &c. communicated by the said observer to the Publisher in a letter, dated June 1. 1674
Authors: Leeuwenhoeck M
Published: December 2006

Sir, Yours of 24
th
of
April
last was very welcome to me; Whence I understood with great contentment, that my Microscopical Communications had not been unacceptable to you and your Philosophical Friends; which hath encouraged me to prosecute such observations, concerning which I shall at present impart to you what follows
An observation made by the learned Dr. Sampson of a man anatomised, whose bowels were found inverted
Authors: Sampson
Published: December 2006

Mr. J. D. sometimes a Minister in
Yorkshire
, was troubled with a Cough, and other Mischiefs; for relief against which he took a journey to
London
, and that, for the most part, on foot: He lived not above a fortnight after he came up.
Extracts of two letters, written by Mr. Flamsteed to Mr. Collins; the one of Novemb. 25. 1674. concerning an instrument to shew the moons true place to a minute or two; as also the writer's design of correcting the hitherto assign'd motions of the sun: The other, of Decemb. 14. 1674. touching the necessity of making new solar numbers, together with an expedient for making trial, whether the refractions in Signor Cassini's tables are just. Extracts of the fifth Letter
Authors: Flamsteed John
Published: December 2006

After my return to
Derby
, I fell to peruse Mr.
Street's
Discourse, and to consider the Contrivance of his
Moon-wiser
; which thought
he
affirms in the Conclusion of his little Tract, to be different from Mr.
Horroxes
; yet I can assure, that for the
Motion
of
Longitude
, tis the very same, and no other than what is taken from my Explication; save that, where I thought the manner of Librating the
Apogéum
was obvious from the Calculation, and needed not to be explained, he hath shewn, how to take it in the Libratory Circle.
An accompt of two books: - I. Les dix Livers d' Architecture de Vitruve, corrigez, & traduits nouvellement en Francois, avec des notes & des figures; par Claude Perrault, de l' Academic Royale des sciences, & Medecin dela faculté de Paris. Imprimé à Paris, 1673. in fol. - II. Anthonii le grand dissertatio de carentia sensûs & cognitionis in Brutis: Londini, apud Joh. Martyn, R. Soc. Typographum, ad insigne companœæ in cæmeterio D. Pauli, 1671
Authors: Perrault Claude
Published: December 2006

The Ingenious and Learned Author of this Version of
Vitruvius
, and of the Notes upon him, considering with himself, that one of the Obstacles to the advancement of Architecture was the want of being able to draw the Precepts of that Art out of its true and genuine source, by reason of the great obscurity of
Vitruvius
, who is the only Writer of the Antients that we have upon this subject; did undertake, by a Translation into the French tongue, and by Notes upon the difficult places, and also by illustrating all with Figures, to render this Author more clear and useful to those, that embrace the profession and practice of that Noble Art.
Advertisements, occasioned by the remarks printed in numb. 114, upon frosts in some parts of Scotland, differing in their anniversary seasons and force from our ordinary frosts in England: Of black winds and tempests: Of the warm or fertilizing temperature and steams of the surface of the earth, stones, rocks, springs, waters, (some in some places, more than other in other places;) of petrifying and metallizing waters: With some hints for the horti-culture of Scotland: By the Reverend and Learned Dr. J. Be
Authors: Beal John
Published: December 2006

Advertisements, occasioned by the remarks printed in numb. 114, upon frosts in some parts of Scotland, differing in their anniversary seasons and force from our ordinary frosts in England: Of black winds and tempests: Of the warm or fertilizing temperature and steams of the surface of the earth, stones, rocks, springs, waters, (some in some places, more than other in other places;) of petrifying and metallizing waters: With some hints for the horti-culture of Scotland: By the Reverend and Learned Dr. J. Beal, F. R. S.; who by way of letter imparted them to the Publisher. Sir, It may seem, by the curious Remarks sent to you from
Scotland
, that we are yet to seek out the Causes and original Source, as well as the Principles and Nature, of Frosts.
Mr. Flamsteads letter of July 24. 1675. to the publisher, relating to another, printed in numb. 110. of these tracts, concerning M. Horroxes lunar systeme
Authors: Flamsteed John
Published: December 2006

I have never before troubled you on the like occasion, which makes me hope, you will pardon this, which I write with no small reluctancy: Nor had I now adventured to concern you with it, if I had not found it frequently the subject of the
Transactions
, to vindicate good Inventions to their proper Authors.
Some observations made in Scotland by that ingenious knight Sir George Makenzie, sent in a letter to Mr. James Gregory, and by him communicated to the publisher
Authors: Makenzie George
Published: December 2006

Sir, It were as needless as fruitless to write a History of our Land as to its ordinary qualities, productions , Scituations, and the like; or of the ordinary methods of manuring it for Corns and Fruits; since I know little practiced here, but what is so over all the Nation.
An extract of a letter of Mr. Lifters, containing some observations made at the Barbado's
Authors: Lister Martin
Published: December 2006

Sir, A Correspondent of mine at the
Barbados
, the Learned Dr.
Thomas Towns
, hath lately furnished me with some Observations in a letter of his dated in that Island
March
26. 1675; which I Shall transcribe for you
Extract of a letter from Mr. Hevelius; being observations by him made at Dantzick, of the comet which began there to appear, Aug. 16. 1682.
Authors: Hevelius Johannes
Published: December 2006

Nuperum Cometam a Vestratibus & Parisiensibus (quan-quam adhuc nihil viderim) optime esse observatum, nullus plane dubito; a me quoque pro viribus, quoties aeris temperies tantum indulsi;
Observationes defectus lunaris grenovici habitæ in observatorio regio Februarij 11/21 1682. p. m. à Johanne Flamsteedio Math. Reg
Authors: Flamsteedio Joanne
Published: December 2006

Ut Testis esset & particeps harum
Observationum
Vespera præcedente
Grenovicum
devenerat D
s
.
Halleius
, aderat brevi postea D
s
.
Haltonus
Amicus meus singularis &
Geometra
peritissimus, cum alijs nonnullis
Matheseos
studiosis.