Correlations Among Atomic Electrons. E-book. Formato PDF Meyer Katzper   -  Forgotten Books, 2017  - 

The wave function obtained in this manner may give fairly good values for the energy but poor approximations to the true ground state wave function. The reason for the aforementioned is that in using the variational principle first order errors in the trial function produce only second order errors in the energy. To obtain a realistic wave function spatial correlation effects must be considered.

African Political Systems. E-book. Formato PDF Meyer Fortes   -  Forgotten Books, 2017  - 

This book is both an experiment in collaborative research and an attempt to bring into focus one of the major problems of African sociology. Many dogmatic opinions are held on the subject of African political organization and are even made use of in administrative practice; but no one has yet examined this aspect of African society on a broad, comparative basis. This book will, we hope, prove the need for and indicate some of the possibilities of such an investigation. Many of the problems it brings into the foreground can only be solved by further research; but the opportunity for such research is rapidly passing and if it is not grasped now may be lost for ever.We regard this book as the first stage of a wider inquiry into the nature and development of African political systems. In addition to further research into native political systems, such an inquiry would include the study of the development of these systems under the influence of European rule. This problem is not only sociologically important, it is of pressing importance to the peoples of Africa and to those who are responsible for governing them.We hope this book will be of interest and of use to those who have the task of administering African peoples. The anthropologist's duty is to present the facts and theory of native social organization as he sees them. It is no light duty; for a thorough training and laborious field investigations are indispensable to its proper performance. Whether or not an anthropologist's findings can be utilized in the practical tasks of administration must be left to the decision of administrators themselves.We are grateful to the International African Institute for sponsoring the publication of this book. Though several of the contributors carried out their field research as Fellows of the Institute, it is in no way responsible for any points of view or opinions expressed in the book. We have to thank Professor Radcliffe-Brown for much help and advice, as well as for the Preface which he has kindly contributed.

A Hand-book of Precious Stones(Illustrated Edition). E-book. Formato PDF Meyer D. Rothschild   -  Ionlineshopping.Com, 2019  - 

The object of this little book is to convey to the merchant, the workman, and the amateur, in a condensed and accurate form, information concerning the various properties of precious stones. Besides drawing freely on a number of authorities, the author has used his practical experience to indicate such tests as an amateur can readily make. Specific gravity, hardness, and dichroism are tests which are easily mastered, and a thorough understanding of these three properties will assist in classifying doubtful gems. Such stones have been dealt with principally as are used in commerce for jewelry and ornamental purposes. The attention of the writer has often been called to the general lack of knowledge among the jewelers regarding precious stones other than diamonds, rubies, sapphires, and emeralds. As there are so many other beautiful and rare gems which nature yields to man, and which are worthy of the jewelers’ art, the author trusts that his book will awaken a new interest in the fascinating study of mineralogy as applied to precious stones, and that at some future day he may feel encouraged to enlarge upon this treatise.