New precision in cosmic ray measurements; Yielding extension of spectrum and indications of bands

Method of measurement of capacities of the order of one cm. — A method is described which leads to greatly increased precision in the measurement of capacities of the order of one electrostatic unit. More penetrating cosmic rays than we have previously found are indicated by a new absorption curve obtained in Gem Lake (9080 ft.) and Lake Arrowhead (5125 ft.) with much greater precision than hitherto possible. Cosmic-ray spectrum. — The new curve affords definite evidence for the existence of bands in the spectrum of cosmic rays. The measurements indicate that the cosmic rays consist chiefly of two bands about three octaves apart of mean absorption coefficients 0.35 and 0.04 to 0.05 per meter of water. The total energy of cosmic rays at the top of the atmosphere is found to be very nearly one-tenth that due to starlight and heat as computed from Seares' data

The origin of the cosmic rays

Maximum energy released by atomic-disintegration (radioactivity.)—From Einstein's equation Mc2=E and Aston's curve the maximum possible energy that can be released in radioactive changes can be computed. The theoretical and experimental values are in satisfactory agreement. Energy released in step-by-step atom-building.—No step-by-step atom-building process can produce rays as penetrating as the observed cosmic rays. The absence of the radiations corresponding to such step-by-step processes probably means that atom-building does not in general occur in this way. The creation of helium out of hydrogen.—About 80 percent of the observed cosmic rays appear to be due to the act corresponding to the sudden union of four positive and two negative electrons into the nucleus of the atom of helium. This produces a cosmic ray of absorption coefficient μ=0.30 per meter of water. The creation of oxygen and silicon out of hydrogen.—The observed cosmic rays of absorption coefficients μ=0.08 and μ=0.04 appear to be produced by the sudden building of positive and negative electrons into atoms of oxygen and silicon, the former act giving rise to a ray of absorption coefficient μ=0.08, the latter to μ=0.04. This last is a definitely observed ray having an energy corresponding to the fall of an electron through 216,000,000 volts. Possible rays due to the creation of iron and to the annihilation of hydrogen.—The cosmic-ray indications are reconcilable with the view that iron is produced by the union in a single act of positive and negative electrons into the atom of iron, but the cosmic rays show no direct indications of the transformation of the whole mass of the hydrogen atom into radiation. Synthetic cosmic-ray curves.—The observed cosmic-ray curve can be built up fairly satisfactorily by the assumption that the relative intensities of the cosmic rays reaching the earth's atmosphere are proportional to the abundance of the common elements in meteorites and the earth's crust, 96 percent of these bodies being made of the four elements, oxygen, magnesium, silicon and iron. The kinetics of atom-building.—While the kinetics of atom-building are more bothersome than the thermodynamics, with suitable assumptions, presented herewith, they may not offer wholly insuperable difficulties. The place of origin of the cosmic rays.—Evidence is presented to show that cosmic rays do not originate in the stars, but only in the depths of space where temperature and densities are practically zero. Cosmic rays and the Second Law of Thermodynamics.—The observed properties of cosmic rays, indicating that the creation of the common elements occurs only in interstellar or intergalactic space, suggest the possibility of avoiding the "wärmetod," and of regarding the universe as already in "the steady state.

A more accurate and more extended cosmic-ray ionization-depth curve, and the present evidence for atom-building

The cosmic-ray ionization-depth curve has been extended at both its upper and lower ends and made more accurate throughout. The absorption coefficients obtained directly from the slope of the curve run from μ=0.35 per m. of water at the top (Pike's Peak) to μ=0.028 at the bottom (80 m. or 262 ft. of water below the top of the atmosphere, thus bringing to light both softer and harder components than the authors had before found. Strong quantitative evidence is presented, on the basis of the Klein-Nishina formula, that the strongest and most absorbable cosmic-ray band arises from the act of formation of helium out of hydrogen. Striking qualitative evidence is found that the three more penetrating bands are due to the formation out of hydrogen of the only other abundant elements oxygen (C, N, O) silicon (Mg, Al, Si, S) and iron (Iron group). Two independent proofs are given that the cosmic-rays enter the earth's atmosphere as photons, namely, (1) they are quite uninfluenced by the earth's magnetic field, and (2) the ionization produced by them in a closed vessel does not increase continually in going to the top of the atmosphere but passes through a maximum. It is shown to follow that the cosmic rays, in coming from their place of origin to the earth have not passed through an amount of matter that is appreciable in comparison with the thickness of the earth's atmosphere and that they must therefore originate in interstellar space rather than in the atmospheres of the stars. Some participation of the nucleus in the absorption of cosmic-rays is brought to light

High altitude tests on the geographical, directional, and spectral distribution of cosmic rays

Intensity of cosmic rays in the high Andes.—Depth-ionization readings taken in Lake Miguilla, Bolivia (alt. 4570 m) and on Lake Titicaca (3820 m) agreed closely with observations in the northern hemisphere previously reported. Intensity of cosmic rays at sea-level.—Three electroscopes which differed considerably in form, wall material and volume, all agreed in giving at sea-level an ionization of 1.4 ions/cc/sec. Effect of Milky Way on cosmic ray intensity.—Two sets of day and night observations, each of three days duration, in a deep valley of the Andes at 4700 m elevation failed to bring to light any difference between the radiation coming in from the plane of the Milky Way and the plane normal thereto. Spectral distribution of the cosmic rays.—A new curve which includes the readings in South America and those published in 1926, analyzed by the method before used, yields absorption coefficients which vary from μ=0.25 per meter of water to μ=0.15. The corresponding wave-lengths, using the Compton equation, are .000525A and .00032A. Ionization at extreme altitudes.—Under the assumption that the largest absorption coefficient, viz. μ=0.25, is valid for the upper regions of the atmosphere, the ionization at any altitude may be calculated, with the aid of the Gold tables, taking the sea-level value as 1.4 I/cc/sec. The total ionization, computed from this data by a graphical integration, for the Millikan and Bowen sounding-balloon observations reported in 1926, shows remarkable agreement with their experimental result. This implies that the wave-lengths of the rays entering the atmosphere are not appreciably different from those at altitudes at which we have ourselves taken observations. Effects of thunder-storms on cosmic rays.—Lake Miguilla, Bolivia, is completely screened from thunder-storm influences and yielded the same value of the cosmic rays as regions not so screened. Also sea-level observations taken in the midst of heavy thunder-storms showed no influence of these on cosmic ray readings

Cognitive Computation sans Representation

The Computational Theory of Mind (CTM) holds that cognitive processes are essentially computational, and hence computation provides the scientific key to explaining mentality. The Representational Theory of Mind (RTM) holds that representational content is the key feature in distinguishing mental from non-mental systems. I argue that there is a deep incompatibility between these two theoretical frameworks, and that the acceptance of CTM provides strong grounds for rejecting RTM. The focal point of the incompatibility is the fact that representational content is extrinsic to formal procedures as such, and the intended interpretation of syntax makes no difference to the execution of an algorithm. So the unique 'content' postulated by RTM is superfluous to the formal procedures of CTM. And once these procedures are implemented in a physical mechanism, it is exclusively the causal properties of the physical mechanism that are responsible for all aspects of the system's behaviour. So once again, postulated content is rendered superfluous. To the extent that semantic content may appear to play a role in behaviour, it must be syntactically encoded within the system, and just as in a standard computational artefact, so too with the human mind/brain - it's pure syntax all the way down to the level of physical implementation. Hence 'content' is at most a convenient meta-level gloss, projected from the outside by human theorists, which itself can play no role in cognitive processing

A Pluralistic Theory of Wordhood

What are words and how should we individuate them? There are two main answers on the philosophical market. For some, words are bundles of structural-functional features defining a unique performance profile. For others, words are non-eternal continuants individuated by their causal-historical ancestry. These conceptions offer competing views of the nature of words, and it seems natural to assume that at most one of them can capture the essence of wordhood. This paper makes a case for pluralism about wordhood: the view that there is a plurality of acceptable conceptions of the nature of words, none of which is uniquely entitled to inform us as to what wordhood consists in

Infrared spectroscopy of HCOOH in interstellar ice analogues

Context: HCOOH is one of the more common species in interstellar ices with abundances of 1-5% with respect to solid H2O. Aims: This study aims at characterizing the HCOOH spectral features in astrophysically relevant ice mixtures in order to interpret astronomical data. Methods: The ices are grown under high vacuum conditions and spectra are recorded in transmission using a Fourier transform infrared spectrometer. Pure HCOOH ices deposited at 15 K and 145 K are studied, as well as binary and tertiary mixtures containing H2O, CO, CO2 and CH3OH. The mixture concentrations are varied from 50:50% to ~10:90% for HCOOH:H2O. Binary mixtures of HCOOH:X and tertiary mixtures of HCOOH:H2O:X with X = CO, CO2, and CH3OH, are studied for concentrations of ~10:90% and ~7:67:26%, respectively. Results: Pure HCOOH ice spectra show broad bands which split around 120 K due to the conversion of a dimer to a chain-structure. Broad single component bands are found for mixtures with H2O. Additional spectral components are present in mixtures with CO, CO2 and CH3OH. The resulting peak position, full width at half maximum and band strength depend strongly on ice structure, temperature, matrix constituents and the HCOOH concentration. Comparison of the solid HCOOH 5.9, 7.2, and 8.1 micron features with astronomical data toward the low mass source HH 46 and high mass source W 33A shows that spectra of binary mixtures do not reproduce the observed ice features. However, our tertiary mixtures especially with CH3OH match the astronomical data very well. Thus interstellar HCOOH is most likely present in tertiary or more complex mixtures with H2O, CH3OH and potentially also CO or CO2, providing constraints on its formation.Comment: 11 pages, 10 figures, accepted by A&