scholarly journals IV. Examination of the proximate principles of some of the lichens

1848 ◽  
Vol 138 ◽  
pp. 63-89 ◽  
Keyword(s):  
Early Period ◽  
Considerable Progress ◽  
Large Species ◽  
Evernia Prunastri ◽  
Cape Of Good Hope ◽  
History Of ◽  
The Subject ◽  
Cursory Examination ◽  
Usual Process ◽  
Made In

The examination of the proximate principles of the lichens, especially of those which yield red colouring matters with ammonia, attracted the attention of some very eminent chemists at a comparatively early period in the history of organic chemistry, and by the labours of Messrs. Robiquet, Heeren, Dumas and Kane, very considerable progress was made in their investigation. Within the last four or five years, Messrs. Schunck, Rochleder, Heldt and Knop have resumed the subject and greatly extended our acquaintance with this interesting but rather difficult depart­ment of organic research. It is but justice to Mr. Schunck to state that he has been by far the most successful cultivator of this field, and that he has done more to elucidate it than any of his predecessors. Nearly two years ago my attention was directed by Dr. Pereira to a kind of Orcella weed which had been recently imported into London from the Cape of Good Hope, but which had been rejected by the London archil manufacturers as unfit for their use, from the small quantity of colouring matter it yielded when subjected to the usual process. The lichen was of considerable size, from eight to ten inches long, and was pronounced by an eminent botanist, Dr. Scouler of Dublin, to whom submitted it, to be merely a large variety of the Roccella tinctoria . I soon ascertained on a very cursory examination, why the lichen had been rejected by the archil makers, for it only contained a small portion of a crystalline principle which yields a red colour with ammonia; I found in its stead, however, a considerable quantity of another crystalline body on which ammonia had no action, and which appeared to have been hitherto undescribed. As it seemed important to ascertain whether or not the red dyes obtained from the various lichens resulted from the action of am­monia on the same crystalline principle, described by Mr. Schunck under the name of Lecanorin, I procured quantities of the several lichens usually employed by the archil makers, and subjected them to investigation. These lichens consisted, —1st, of a large species of Roccella tinctoria from the west coast of South America; 2nd, of the R. tinctoria from the Cape of Good Hope; 3rd, of the R. Montagnei from Angola; and 4th, of the Lecanora tartarea . I had made considerable progress with the investigation of these lichens, and also with that of the Evernia prunastri , when Mr. Schunck’s elaborate paper on the Angola lichen appeared, from which it was evident that at least two varieties of the red colouring principle existed in these lichens. I now therefore proceed to give a detail of the results of these examinations.

Innovation in SiAlON Ceramics

2007 ◽  
Vol 352 ◽  
pp. 137-146
Author(s):  
Derek P. Thompson
Keyword(s):  
Considerable Progress ◽  
Structural Ceramics ◽  
Engineering Applications ◽  
Microstructure And Properties ◽  
Structural Applications ◽  
Significant Step ◽  
History Of ◽  
The Subject ◽  
Made In

The discovery of sialons in 1971 was a significant step in the history of nitrogen ceramics, because it broadened the field into a wider range of chemistry, and simultaneously increased the flexibility to modify microstructure and properties. During the last 35 years this has resulted in the development of a spectrum of materials, mainly based on the α- and β- structural forms. However, the subject has remained broadly within the scope of structural ceramics. During the 1990s, a range of new sialon derivatives were prepared with a more varied starting chemistry, and the corresponding final materials demonstrated a correspondingly wider variety of structural complexities. In response, many sialon researchers have started to broaden their interests beyond the limiting horizon of structural applications, and considerable progress has been made in the development of transparent and coloured materials, and also derivatives with useful electronic properties.This enlargement of the sialons field is still in its infancy, but promises to generate a much wider spectrum of materials, which can be tailored to meet the increasingly multifunctional requirements of modern day engineering applications.

XXIII. On the water-barometer erected in the hall of the Royal Society

1832 ◽  
Vol 122 ◽  
pp. 539-574 ◽  
Keyword(s):  
Royal Society ◽  
Physical Science ◽  
The Other ◽  
Metallic Tube ◽  
French Academy ◽  
History Of ◽  
The Subject ◽  
The Common ◽  
Academy Of Sciences ◽  
Made In

I have for some time entertained an opinion, in common with some others who have turned their attention tot he subject, that a good series of observations with a Water-Barometer, accurately constructed, might throw some light upon several important points of physical science: amongst others, upon the tides of the atmosphere; the horary oscillations of the counterpoising column; the ascending and descending rate of its greater oscillations; and the tension of vapour at different atmospheric temperatures. I have sought in vain in various scientific works, and in the Transactions of Philosophical Societies, for the record of any such observations, or for a description of an instrument calculated to afford the required information with anything approaching to precision. In the first volume of the History of the French Academy of Sciences, a cursory reference is made, in the following words, to some experiments of M. Mariotte upon the subject, of which no particulars appear to have been preserved. “Le même M. Mariotte fit aussi à l’observatoire des experiences sur le baromètre ordinaire à mercure comparé au baromètre à eau. Dans l’un le mercure s’eléva à 28 polices, et dans Fautre l’eau fut a 31 pieds Cequi donne le rapport du mercure à l’eau de 13½ à 1.” Histoire de I'Acadérmie, tom. i. p. 234. It also appears that Otto Guricke constructed a philosophical toy for the amusement of himself and friends, upon the principle of the water-barometer; but the column of water probably in this, as in all the other instances which I have met with, was raised by the imperfect rarefaction of the air in the tube above it, or by filling with water a metallic tube, of sufficient length, cemented to a glass one at its upper extremity, and fitted with a stop-cock at each end; so that when full the upper one might be closed and the lower opened, when the water would fall till it afforded an equipoise to the pressure of the atmo­sphere. The imperfections of such an instrument, it is quite clear, would render it totally unfit for the delicate investigations required in the present state of science; as, to render the observations of any value, it is absolutely necessary that the water should be thoroughly purged of air, by boiling, and its insinuation or reabsorption effectually guarded against. I was convinced that the only chance of securing these two necessary ends, was to form the whole length of tube of one piece of glass, and to boil the water in it, as is done with mercury in the common barometer. The practical difficulties which opposed themselves to such a construction long appeared to me insurmount­able; but I at length contrived a plan for the purpose, which, having been honoured with the approval of the late Meteorological Committee of this Society, was ordered to be carried into execution by the President and Council.

Depressive Illnesses in Children and Adolescents: A Review of Current Concepts

1985 ◽  
Vol 30 (2) ◽  
pp. 119-129 ◽  
Author(s):  
B.J. Mcconville ◽  
R.T. Bruce
Keyword(s):  
Children And Adolescents ◽  
Current Knowledge ◽  
Considerable Progress ◽  
Childhood And Adolescence ◽  
Age Related ◽  
Developmental Age ◽  
The Subject ◽  
Made In

Considerable progress has been made in our understanding of depressive illnesses in childhood and adolescence, especially over the last several years. A number of major books on the subject have now appeared, along with a large number of individual papers. This paper attempts to summarize current knowledge, and indicates developmental, age-related and other issues which still require further study.

scholarly journals Comparative analysis of the works published in periodicals and as part of the books, with major texts of A. E. Kulakovsky

Litera ◽  
2020 ◽  
pp. 47-60
Author(s):  
Aleksandr Pavlovich Nogovitsyn
Keyword(s):  
Comparative Analysis ◽  
Early Period ◽  
Special Significance ◽  
The Past ◽  
Literary Heritage ◽  
History Of ◽  
The Subject ◽  
New Perspective ◽  
Unpublished Works

This article examines the works of A. E. Kulakovsky based on theoretical positions of D. S. Likhachev and practical data from commentaries to the volume II of A. E. Kulakovsky (author P. V. Maksimov), as well as conducts comparative analysis of the early versions with major texts of A. E. Kulakovsky. The subject of this research is the comparative analysis of A. E. Kulakovsky's early publications with major texts. The goal consists in determination and description of the authorial editing and revisions, which allows substantiating their motives for, as well as tracing the evolution of author’s thought. The discrepancies between the texts of early period and major text are viewed as improvements: addition of lines, substitution of separate words, rearrangement lines and stanzas. The novelty of this study consists in substantiation of early publications of A. E. Kulakovsky and lifetime edition as the subject of textological research. From this perspective, early publications of the works of A. E. Kulakovsky's are attributed to as research materials of cross-disciplinary nature: as the testimonies of the stage of establishment of Yakut literature as a whole, and as the variants of writer's major texts that reveal the history of his works in particular. The relevance is defined by the fact that special textological studies of poet’s separate works, including profound examination of historiographical part of his literary heritage, are currently of special significance. Over the past decade, a sizeable corpus of new documents related to A. E. Kulakovsky’s biography, including the unpublished works and scientific writings, has been revealed; this gives a new perspective on the already familiar materials in the context of analysis of his evolution as a writer and the history of publication of his works in the XX century.

scholarly journals Star Formation: From OB Associations to Protostars

1987 ◽  
Vol 115 ◽  
pp. 1-18 ◽  
Author(s):  
Charles J. Lada
Keyword(s):  
Star Formation ◽  
Stellar Evolution ◽  
Large Body ◽  
Apparent Paradox ◽  
International Astronomical ◽  
Critical Experiment ◽  
History Of ◽  
The Subject ◽  
Astrophysical Research ◽  
Made In

The study of star formation is a relatively young discipline of the field of astronomy. Up until the mid point of the twentieth century only a most rudimentary understanding of the subject was possible. This is because prior to that time there did not exist any substantive body of empirical data which could be used to critically test even the most basic hypotheses concerning stellar origins. However, as a result of impressive advances in observational technology and in our understanding of stellar evolution during the last forty years, the subject of star formation has developed into one of the most important branches of modern astrophysical research. A large body of observational data and a considerable literature pertaining to this subject now exist and a significant fraction of the international astronomical community devotes their efforts towards trying to comprehend the origins of stars and planets. Yet, despite these efforts we have yet to observationally identify, with any certainty, a single object in the process of stellar birth! Moreover, we have not yet produced a viable theory of star formation, one capable of being tested and refined by critical experiment. In many ways, stellar birth is as much a mystery today as it was forty years ago. However, there can be little doubt that during the last two decades truly revolutionary progress has been made in the quest to understand the star formation process in our galaxy. This apparent paradox in the state of our knowledge concerning stellar origins is resolved with the realization that the history of the study of star formation has been a history of the study of progressively earlier and earlier stages of stellar evolution. Indeed, it is in precisely this area of endeavor that we have learned so much.

scholarly journals The History of Solar Prominence Research: Historical Introduction to IAU Colloquium No. 167 “New Perspectives on Solar Prominences”

1998 ◽  
Vol 167 ◽  
pp. 11-19 ◽  
Author(s):  
Einar Tandberg-Hanssen
Keyword(s):  
Early Period ◽  
Solar Prominence ◽  
Physical Conditions ◽  
Solar Prominences ◽  
Comprehensive Picture ◽  
History Of ◽  
Global Nature ◽  
Made In ◽  
Coronal Structures

AbstractWe trace the history of observational solar prominence research from the early period when total solar eclipses provided the only means of observation, via the introduction of photography and spectroscopy in the 1860’s, to the present epoch when application of the Zeeman and the Hanle effects makes possible determination of the all-important magnetic fields in prominences.Dividing prominence models into two classes, those that treat the support of the prominence against gravity and those concerned with the physical conditions in the prominence plasma itself, we describe the progress made in both classes of models since the 1950’s, when the first models were proposed. Finally, we comment on the necessity of combining aspects of the two classes of prominence models into a comprehensive picture that can account for the global nature of prominence support and stability, and where the adjacent coronal structures play an important role.

On the Origin and Progress of the Calculus of Probabilities

1856 ◽  
Vol 6 (3) ◽  
pp. 134-147
Author(s):  
Samuel Brown
Keyword(s):  
Human Life ◽  
Early Period ◽  
Daily Routine ◽  
Life Assurance ◽  
History Of ◽  
The Subject

The application of the doctrine of chances to questions connected with the money values of contingencies depending on human life is now become so common, in this and many other countries, that we may he apt to forget its origin and the process by which it arrived at its present degree of improvement. Although the history of this calculus may be well known to some members of this Institute, there may be others whose time is, perhaps, too occupied to allow of more than the mere study of the calculations and formulæ necessary for the daily routine of a Life Assurance Office, and who may not be aware of the number of other subjects to which, at an early period, the calculus of probabilities was suggested to be applied. I hope, therefore, that in taking a rapid glance at the changes and improvements effected since the first crude ideas on the subject, I may not only be able to excite an increased interest in the science, but induce a further extension of its usefulness.

scholarly journals XXIII.—Some Account of the Recent Progress of Sanskrit Studies

1863 ◽  
Vol 23 (2) ◽  
pp. 253-283
Author(s):  
J. Muir
Keyword(s):  
Present State ◽  
Recent Progress ◽  
Indian Literature ◽  
History Of ◽  
The Subject ◽  
Made In

In compliance with the desire which the Council have done me the honour to express, I have drawn up the following account of the recent progress and present state of Sanskrit studies, prefixing such an outline of the earlier history of these researches as may serve to complete the review, and render it more easily intelligible.In this sketch I do not profess to communicate anything new, but merely seek to present such a summary of the results already obtained, as may convey to those who have not bestowed any special attention on the subject some idea of the character and affinities of the Sanskrit language, and of the nature and contents of Indian literature, as well as of the advances which have of late years been made in the principal branches of the study.

scholarly journals Applying the Canon in Islam

1998 ◽  
Vol 15 (2) ◽  
pp. 112-115
Author(s):  
Yusuf Talal DeLorenzo
Keyword(s):  
Human Nature ◽  
History Of Religion ◽  
History Of ◽  
The Subject ◽  
Use Of Models ◽  
Made In

According to Smith, the Ndembu diviner applies a "canon" of twenty-four fixedobjects to a client's situation, first selecting a few of the objects by shaking the basket,interpreting the selected objects according to a range of meanings fixed by pub­lic convention, and matching the meanings to the client's particular condition.Brannon Wheeler, in his Introduction to Applying the Canon in IslamWhen the idolaters inimical to the message of Muhammad, upon him bepeace, attempted to criticize the Qur'an for its use of the lowly and the trivial inits rhetorical repertoire, the following verse was revealed in reply.Behold, God does not disdain to propound a parable of a gnat, or of something evenless than that. Now, as for those who have attained to faith, they know that it is thetruth from their Sustainer whereas those who are bent on denying the truth say,What could God mean by this parable? (2:26)This exchange then became the basis for djscussion and debate among theclassical Arabic rhetoricians on the subject of what might and what might not besuitable for use in similes, metaphors, and other comparative ljterary devices.That this debate shouJd be recalled at the outset of a review of a work dealingwith Hanafi fiqh scholarship might seem slrangely out of place. Yet, once onehas acqurunted oneself with the underlying premise of this work, one cannothelp but recall the classical debate and the verses of Qur'anic scripture so oftencited in regard to it. What lies at the heart of the matter is that comparisonsdrawn between disparate and remote subjects are sometimes delightful andsometimes awful. This, after all, is the stuff of literature. There are some comparisons,however, that are simply offensive.In fact, there are some things people just don't like to see compared at all.Period. Things held near and dear often fall under this category, things like one'sreligion, ethnicity, culture, and so on. This is human nature. And that is dangerousground.Of course, I've oversimplified the matter. ln fact, I'm going in a direction thatwas certrunly not intended by the author for his readership. Wheeler's Applyingthe Canon in Islam is not a work of literature. Likewise, hjs use of models andexamples from other disciplines, like anthropology and the history of religion,is a methodological rather than a literary choice. But the fact remains that thechoice Professor Wheeler has made in this matter is one that will not likely bemet with objectivity by Muslims. If I may venture a comparison of my own, thisis rather akin to inviting a Muslim to partake of a meal, a sumptuous and hearty ...

scholarly journals The probability of excitation by electron-impact in neon

1929 ◽  
Vol 122 (790) ◽  
pp. 430-442 ◽  
Keyword(s):  
Electron Impact ◽  
Transition Probabilities ◽  
Inert Gases ◽  
Considerable Progress ◽  
Wave Mechanics ◽  
Quantum Jump ◽  
Modern Physics ◽  
The Subject ◽  
Made In

The importance of “transition-probabilities” in modern physics is steadily increasing, and our knowledge of them has of late also made considerable progress; the values of several of them have now even been calculated directly by the wave-mechanics. The probability of excitation of a quantum-jump by electron-impact is, however, a noticeably backward branch of the subject: not only is it as yet almost untouched by theory; the experimental determinations are also somewhat scanty, more especially in the case of the inert gases. It is therefore of interest that some recent data of Townsend and McCallum allow an estimate to be made in the case of neon. It is not indeed possible to obtain from them the probability of any definite excitation, but a sort of “average of the sum of all probabilities” can be evaluated with fair certainty. The problem has not been attempted by the authors, and appears in fact difficult to treat by methods hitherto published; the line here developed seems to be new.

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