Heavy Oil as Fuel for Internal-Combustion Engines (Classic Reprint)

Download Heavy Oil as Fuel for Internal-Combustion Engines (Classic Reprint) PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780666691828
Total Pages : 40 pages
Book Rating : 4.6/5 (918 download)

DOWNLOAD NOW!


Book Synopsis Heavy Oil as Fuel for Internal-Combustion Engines (Classic Reprint) by : Irving C. Allen

Download or read book Heavy Oil as Fuel for Internal-Combustion Engines (Classic Reprint) written by Irving C. Allen and published by Forgotten Books. This book was released on 2018-03 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Heavy Oil as Fuel for Internal-Combustion Engines This gas oil, as its name implies, can be cracked in hot retorts and an excellent illuminating gas made therefrom (3 or it may be burned with good results as a fuel under steam boilers. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Heavy Oil as Fuel for Internal-combustion Engines

Download Heavy Oil as Fuel for Internal-combustion Engines PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 48 pages
Book Rating : 4.3/5 (91 download)

DOWNLOAD NOW!


Book Synopsis Heavy Oil as Fuel for Internal-combustion Engines by : Irving Cowan Allen

Download or read book Heavy Oil as Fuel for Internal-combustion Engines written by Irving Cowan Allen and published by . This book was released on 1913 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Heavy Oil As Fuel for Internal-Combustion Engines

Download Heavy Oil As Fuel for Internal-Combustion Engines PDF Online Free

Author :
Publisher : Palala Press
ISBN 13 : 9781340687960
Total Pages : 46 pages
Book Rating : 4.6/5 (879 download)

DOWNLOAD NOW!


Book Synopsis Heavy Oil As Fuel for Internal-Combustion Engines by : Irving Cowan Allen

Download or read book Heavy Oil As Fuel for Internal-Combustion Engines written by Irving Cowan Allen and published by Palala Press. This book was released on 2015-08-31 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.

Heavy Oil as Fuel for Internal-combustion Engines, by Irving C. Allen

Download Heavy Oil as Fuel for Internal-combustion Engines, by Irving C. Allen PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 36 pages
Book Rating : 4.:/5 (458 download)

DOWNLOAD NOW!


Book Synopsis Heavy Oil as Fuel for Internal-combustion Engines, by Irving C. Allen by : Irving C. Allen

Download or read book Heavy Oil as Fuel for Internal-combustion Engines, by Irving C. Allen written by Irving C. Allen and published by . This book was released on 1913 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Papers on Internal Combustion Engines (Classic Reprint)

Download Papers on Internal Combustion Engines (Classic Reprint) PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780656350780
Total Pages : 598 pages
Book Rating : 4.3/5 (57 download)

DOWNLOAD NOW!


Book Synopsis Papers on Internal Combustion Engines (Classic Reprint) by : Institute Of Marine Engineers

Download or read book Papers on Internal Combustion Engines (Classic Reprint) written by Institute Of Marine Engineers and published by Forgotten Books. This book was released on 2018-02-11 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Papers on Internal Combustion Engines The heavy oil engine was brought forth at a time when there were abundant mechanical resources for its development and in consequence there has been rapid progress in design. One of the results of this quick evolution has been that this type of engine has gone ahead of popular ideas and is intimately known to only a comparatively small section of marine engineers. The desire to rectify this state of affairs led the Council of the Institute of Marine Engineers to organise and publish the series of lectures which comprise this volume; the need for such a book seemed to be pronounced, for although many valuable works on the theory and design of internal combustion engines exist, it was considered that the experiences of those who had been in charge 'of them in the experimental stage and in service would be of great value to those who desired a closer acquaintance with this new form of prime mover. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Heavy Oil As Fuel for Internal-Combustion Engines

Download Heavy Oil As Fuel for Internal-Combustion Engines PDF Online Free

Author :
Publisher : Theclassics.Us
ISBN 13 : 9781230458694
Total Pages : 22 pages
Book Rating : 4.4/5 (586 download)

DOWNLOAD NOW!


Book Synopsis Heavy Oil As Fuel for Internal-Combustion Engines by : Irving Cowan Allen

Download or read book Heavy Oil As Fuel for Internal-Combustion Engines written by Irving Cowan Allen and published by Theclassics.Us. This book was released on 2013-09 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 edition. Excerpt: ... ANIMAL OILS. Animal oils, such as lard oil, of specific gravity 0.913 to 0.919, like the vegetable oils, can be used successfully, but are high priced and only in an emergency are they to be considered as a fuel. ALCOHOLS. A mixture of 80 per cent alcohol and 20 per cent benzene (268) has been burned successfully in the heavy-oil engine. However, it has been found advisible to warm the engine by first starting it on a more volatile petroleum product, as benzine. WOOD OILS. Wood oils or creosote distillates of specific gravity 0.841 to 0.877 (269) have also been used to a limited extent with success. In short, the following oils and mixtures of them have been used successfully in heavy-oil engines, provided they were mobile, free from free carbon, grit, and water, and were low in sulphur: Petroleum products: Gasoline; lamp oils of all kinds; naphthas; gas oils; fuel-oil distillates; "masut" or residues from the crude oils of Russia; and crudes, if mobile. "Steinkohle" oil products: Heavy oils; anthracene oils; and tar oils. Bituminous oils: Retort oils of all kinds. Lignite products: Benzene; solar oils; paraffin distillates; and creosote oils. Turf oils: Creosote oils. Shale oils. Vegetable oils: Peanut oil; coconut oil; castor-bean oil; cottonseed oil; and palm-seed oil. Animal oils. Alcohols. Wood oils: Creosotes. TREATMENT OF HEAVY OILS TO MAKE THEM MOST SUITABLE FOR FUEL. It has been stated in the previous pages that any fuel that will flow freely can be burned in a heavy-oil engine. Though this in a measure is true, heavy tarry oils, if not kept perfectly fluid by heating, will cool and tend to clog the pipes and valves. It is advisable, therefore, to first subject the tarry oils to a distillation (270), distilling over everything...

Gas and Oil Engines, and Gas Producers

Download Gas and Oil Engines, and Gas Producers PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 248 pages
Book Rating : 4.M/5 ( download)

DOWNLOAD NOW!


Book Synopsis Gas and Oil Engines, and Gas Producers by : American School (Lansing, Ill.)

Download or read book Gas and Oil Engines, and Gas Producers written by American School (Lansing, Ill.) and published by . This book was released on 1913 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Internal Combustion Engine

Download The Internal Combustion Engine PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 352 pages
Book Rating : 4.3/5 (243 download)

DOWNLOAD NOW!


Book Synopsis The Internal Combustion Engine by : Harry Egerton Wimperis

Download or read book The Internal Combustion Engine written by Harry Egerton Wimperis and published by . This book was released on 1909 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Production of Gasoline by Cracking Heavier Oils (Classic Reprint)

Download Production of Gasoline by Cracking Heavier Oils (Classic Reprint) PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780484799416
Total Pages : 60 pages
Book Rating : 4.7/5 (994 download)

DOWNLOAD NOW!


Book Synopsis Production of Gasoline by Cracking Heavier Oils (Classic Reprint) by : E. W. Dean

Download or read book Production of Gasoline by Cracking Heavier Oils (Classic Reprint) written by E. W. Dean and published by Forgotten Books. This book was released on 2018-03-03 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Production of Gasoline by Cracking Heavier Oils The ordinary processes of refining crude petroleum yield a series of products differing widely in properties and commercial desirability. Those required for the smaller types of internal combustion engines, such as are now generally used in airplanes, motor boats, farm trac tors, motor trucks, and automobiles, are in greatest demand. Kero sene and fuel oil, which are used to produce light, heat, or power in competition with other more plentiful resources, such as coal, are less desirable with regard both to commercial profit and the conser vation of natural resources. Of the two types of products used in internal combustion engines lubricants and gasoline - the former does not seem as yet to Offer a problem in the conservation of resources. Gasoline is, however, being produced in such quantities that its continued use on the pres ent scale threatens to bring about the practical exhaustion of the country's underground supply of crude petroleum in the course of a few generations at most. The Bureau of Mines knows of no more important problem facing the country to - day than the conservation of this valuable natural resource, and has undertaken through the present investigation and other studies to promote greater efficiency in the utilization of crude petroleum. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The Cycles of Gas and Oil Engines (Classic Reprint)

Download The Cycles of Gas and Oil Engines (Classic Reprint) PDF Online Free

Author :
Publisher :
ISBN 13 : 9781332820498
Total Pages : 90 pages
Book Rating : 4.8/5 (24 download)

DOWNLOAD NOW!


Book Synopsis The Cycles of Gas and Oil Engines (Classic Reprint) by : James D. Roots

Download or read book The Cycles of Gas and Oil Engines (Classic Reprint) written by James D. Roots and published by . This book was released on 2016-06-13 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The Cycles of Gas and Oil Engines The words internal combustion engines contain a fairly approximate descriptive definition of gas, oil, and Spirit engines 3 and for the later period of these motors - for the whole may be conveniently divided into two periods, that before and that subsequent to the introduction of the Otto engines - this title is possibly the best that can be devised, yet as these words will necessarily include gunpowder, gun-cotton, and all similar fulminating engines, it is not sufficiently accurate for a work upon the cycles of these motors. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Gas and Petroleum Engines

Download Gas and Petroleum Engines PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780267970179
Total Pages : 650 pages
Book Rating : 4.9/5 (71 download)

DOWNLOAD NOW!


Book Synopsis Gas and Petroleum Engines by : William Robinson

Download or read book Gas and Petroleum Engines written by William Robinson and published by Forgotten Books. This book was released on 2018-02-06 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Gas and Petroleum Engines: A Practical Treatise on the Internal Combustion Engine This book is intended to aid students and practical men in studying Gas and Petroleum Engines, and the principles that underlie and control their action, so as to put the practical 'man in a position to test the performance of these engines, and to make an intelligent use of his own experience and observations. Several years' experience in the teaching of technical students and practical workmen has led me to bring out this work, which I have endeavoured to make complete in itself as a text-book on the subject. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Liquid Fuels for Internal Combustion Engines

Download Liquid Fuels for Internal Combustion Engines PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 266 pages
Book Rating : 4.:/5 (3 download)

DOWNLOAD NOW!


Book Synopsis Liquid Fuels for Internal Combustion Engines by : Harold Moore

Download or read book Liquid Fuels for Internal Combustion Engines written by Harold Moore and published by . This book was released on 1920 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Internal Combustion Engines

Download Internal Combustion Engines PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780282783068
Total Pages : 446 pages
Book Rating : 4.7/5 (83 download)

DOWNLOAD NOW!


Book Synopsis Internal Combustion Engines by : Robert L. Streeter

Download or read book Internal Combustion Engines written by Robert L. Streeter and published by Forgotten Books. This book was released on 2017-07-05 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Internal Combustion Engines: Theory and Design; A Text Book on Gas-and Oil-Engines for Engineers and Students in Engineering General Combustion Combustion of Carbon Combustion of Hydrogen Combustion of Hydrocarbons Atmospheric Air Volume of Air Required for Combustion Air Required for a Compound Gas Air Per Cubic Foot of Gas Volume of Prod nots of Combustion Heating Value of Fuels Containing Hydro gen The Gas Calorimeter The Mahler Bomb Calorimeter Heating Value of Fuel by Formula Specific Heat and Flame Temperature Density of Gases Heating Value Per Unit Vol ume Vapor Pressure. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Handbook on Care and Operation of Gasoline Engines (Classic Reprint)

Download Handbook on Care and Operation of Gasoline Engines (Classic Reprint) PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780666508133
Total Pages : 126 pages
Book Rating : 4.5/5 (81 download)

DOWNLOAD NOW!


Book Synopsis Handbook on Care and Operation of Gasoline Engines (Classic Reprint) by : United States Coast Guard

Download or read book Handbook on Care and Operation of Gasoline Engines (Classic Reprint) written by United States Coast Guard and published by Forgotten Books. This book was released on 2018-02-27 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Handbook on Care and Operation of Gasoline Engines When crude Oil is Slightly heated gases are given Off which may be condensed to a liquid by cooling. This liquid is not at all like the original oil, but is quite colorless, light as compared with crude oil, and easily vaporized (changed to the form of gas) by slight heating. The crude oil, if further heated, con tinues to give ofi gases which, when condensed, form a liquid much like that first obtained, but slightly heavier and not quite so easily vaporized. This process can be continued and a whole series of liquids Obtained, each slightly heavier and less easily vaporized than the one before it, until the product is no longer colorless, but yellow, green, or brown. The first liquids thus obtained are not of much use commercially. They vaporize so rapidly that explosive gas is generated at ordinary temper atures, making these oils too dangerous for ordinary use. After these, however, comes a series of oils which are of great value in modern life, known as gasoline, kerosene, and lubricating oils. Gasoline is the part of crude Oil obtained after the lighter liquids referred to above have been distilled OE and while the heating proceeds from about 230° F. To about 280° F. Kerosene is obtained as the distillation continues between 280° and After that, lubricating oils are produced. The remainder, a thick, heavy, sticky oil, is suitable for use as fuel, and is used in some parts of the country for firing locomotives, making steam for factories and power plants, and as fuel on steam vessels. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Gas and Petroleum Engines (Classic Reprint)

Download Gas and Petroleum Engines (Classic Reprint) PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780265884966
Total Pages : 166 pages
Book Rating : 4.8/5 (849 download)

DOWNLOAD NOW!


Book Synopsis Gas and Petroleum Engines (Classic Reprint) by : Raoul Marquis

Download or read book Gas and Petroleum Engines (Classic Reprint) written by Raoul Marquis and published by Forgotten Books. This book was released on 2017-12 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Gas and Petroleum Engines The suitability Of oil engines for the purpose has awakened a widespread interest in them. The Editor therefore hopes that this little volume will be especially welcome to non-technical readers who like to keep ahead Of the times in matters Of such universal importance. One chapter deals exclusively with the theory of the gas engine, but the non-technical mind Should have no fear, for mathematics have been as far as possible avoided. It may also serve to dispel wrongful notions concerning the practical limits of the efficiency of gas engines which. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Gas, Gasoline and Oil Engines (Classic Reprint)

Download Gas, Gasoline and Oil Engines (Classic Reprint) PDF Online Free

Author :
Publisher : Forgotten Books
ISBN 13 : 9780267621897
Total Pages : 224 pages
Book Rating : 4.6/5 (218 download)

DOWNLOAD NOW!


Book Synopsis Gas, Gasoline and Oil Engines (Classic Reprint) by : Archie Frederick Collins

Download or read book Gas, Gasoline and Oil Engines (Classic Reprint) written by Archie Frederick Collins and published by Forgotten Books. This book was released on 2018-02-02 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Gas, Gasoline and Oil Engines And this is equally true whether you are a man or a woman, a boy or a girl, for it is only a question of time until you will find yourself face to face With one of them. If you are ignorant of how they are made and work you will, more than likely, go through the harrowing experiences and make the costly mis takes that countless others have made before you. This is a great pity, for it is easy to know all about gas, gasoline and oil engines if you start right, and to do so all you need is to read this book through carefully. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

The Gas-Engine a Treatise on the Internal-Combustion Engine Using Gas

Download The Gas-Engine a Treatise on the Internal-Combustion Engine Using Gas PDF Online Free

Author :
Publisher :
ISBN 13 : 9781331823032
Total Pages : 596 pages
Book Rating : 4.8/5 (23 download)

DOWNLOAD NOW!


Book Synopsis The Gas-Engine a Treatise on the Internal-Combustion Engine Using Gas by : Frederick Remsen Hutton

Download or read book The Gas-Engine a Treatise on the Internal-Combustion Engine Using Gas written by Frederick Remsen Hutton and published by . This book was released on 2015-07-14 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from The Gas-Engine a Treatise on the Internal-Combustion Engine Using Gas: Gasoline, Kerosene, Alcohol, or Other Hydrocarbon as Source of Energy When a previous treatise by the author was published under the title of "The Mechanical Engineering of Power Plants," it was suggested by one of his most gifted critics that the title should be amended because the book did not cover the power-plant practice which uses gas-engines. The point was well taken, but the omission was intentional. To have included the gas-engine would have made that book inconveniently bulky. Furthermore, the treatment of the gas-engine must be essentially different from that given to the steam-engine, and at that time the state of the art, both practically and scientifically, did not admit of the preparation of a satisfactory and exhaustive discussion. Since that time, however, there has grown up a largely increased appreciation of the fuel value of what were called the waste gases from the blast-furnace, and a wider extension of the manufacture of fuel gas in producers. The gas-engine has been extensively applied in the departments of electric lighting, and of compression, both of air and gas. It is since that time also that there has appeared the exacting demand for Motors for self-propelled vehicles and for small launches, so that it has become possible to undertake that for which the time was not ripe when the criticism was made. There was, at that time, little distinctively American practice to be studied, but the principal work had been done in England, Germany, and Belgium. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.