page_title: Nicholas Procter Burgh
section_title: The Indicator Diagram Practically Considered, 1869
hierarchical_section_title: Nicholas Procter Burgh / Works / The Indicator Diagram Practically Considered, 1869
caption_attribution_description: English: Practical definition of an Indicator diagram, 1869
context_page_description: Nicholas Procter Burgh was a British marine engineer, known for his work on marine engines, marine engineering, screw propulsion, boilers and boiler-making, and the indicator diagram.
context_section_description: One of the later books Burgh published was on the indicator diagram, since the early 20th century named pressure volume diagram or PV diagram. This was the first (and only) book solely devoted to the indicator diagram, its theoretical background, and its applications. This type of diagram was developed late 18th century in the workshop of Boulton and Watt by James Watt and his employee John Southern (1758–1815). It was used to improve the efficiency of engines, and kept a trade secret until the 1830s. In the 1850s William John Macquorn Rankine in 1859/1866 was one of the first to give a detailed description of the device. According to Miller (2011): 
  A detailed and influential treatment of the indicator within the framework of a newly developing 'engineering science' was given by W. J. Macquorn Rankine, in his A Manual of the Steam Engine (1859). Rankine not only reconceptualized the indicator diagram as what he called the 'diagram of energy', but also offered a substantial scientific account of how departures of real indicator diagrams from the ideal could be linked to operating characteristics of engines and of the indicator itself.
  More works in those days described the diagram and its origin, such as in the 1865 Handbook of the steam-engine by the British engineer John Bourne. In the chapter on "The power and performance of engines" he introduced the device and made extensive use of indicator diagrams. In the first chapter of his 1869 work Burgh gave a general description of the state of the art on this subject in those days: 
  A VERY large proportion of the young members of the engineering profession look at an indicator diagram as a mysterious production; and even supposing that they comprehend how it is formed, they do not understand the causes for the various forms of figures. There is, therefore undoubtedly, room for a practical work on the subject which shall deal with the matter just as a learner requires : leading him on step by step without slipping, and impressing on his mind all the realities of the case... The best course of instruction for the young engineer then is, that the truth of each minute portion of the subject before him be laid bare, so that he can comprehend it. When he understands thus far, obviously his knowledge will enable him to put the same into practice boldly : for by being acquainted with the ground-work of the subject, he is master also to a great extent of the result of his labours.
  In the preface Burgh explained, that the book describes all inns and outs of the PV diagram in the following ten steps:
  Chapter I. contains the description and use of the indicator, illustrating, at a working scale, Messrs. Maudslays' and Mr. Richards' Indicators (see image).
  Chapter II. is under the heading, "How to take an indicator diagram correctly:" which treats of the action of the steam in the cylinder ; the definition of the diagram ; correct indicator gear for horizontal, vertical, and oscillating engines, and indicating notes.
  Chapter III. deals with the proof of atmospheric pressure and particulars of steam pressures, and includes rules and tables bearing on the subject, with practical examples and illustrations.
  Chapter IV. is a complete description and illustration of the theoretical geometry of the indicator diagram in a more practical manner than hitherto published.
  Chapter V. is the practical geometry of the indicator diagram, which fully explains the frontispiece plate and other figures in connection with it.
  Chapter VI. commences the illustrations of indicator diagrams and gear constructed by the firms I have mentioned, and others whose names are noted under the figures : this chapter contains twenty-one diagrams from ordinary modern screw engines of all classes; three from compound engines ; three of steam-launch engines ; and two illustrations of indicator gear for return acting engines.
  Chapter VII. is devoted to diagrams taken from the most modem paddle-engines, and contains eighteen illustrations of them; also the most improved indicator gear by Messrs. Penn and Napier, for oscillat
caption: Practical definition of Indicator diagram, 1869.
exif: {"Image Artist": "Karina", "Image ExifOffset": "2130", "Image XPAuthor": "Karina", "Image Padding": "[]", "EXIF DateTimeOriginal": "2015:06:04 00:12:34", "EXIF DateTimeDigitized": "2015:06:04 00:12:34", "EXIF SubSecTimeOriginal": "01", "EXIF SubSecTimeDigitized": "01", "EXIF Padding": "[]"}