Current issue of eRittenhouse
TABLE OF CONTENTS
Thomas B. Greenslade on The Lecture Table Galvanometer describes a variety of galvanometers, meters to show the level of electrical current, that were used in physics classes with which the instructor could demonstrate the relationship of voltage, resistance and current, for instance. He also discusses the effectiveness of such demonstrations during classes in the learning process of students. Tom’s second paper, Apparatus for Natural Philosophy: The Rheostat traces the development in the 19th and 20th centuries of coil wound devices to control voltage across an electrical circuit and to measure electrical current flow is examined. Tom’s most recent paper, Reflections on a 1950 Cenco Catalogue, looks at examples of apparatus widely used in physics labs and that were frequently acquired from Central Scientific, aka Cenco. The origins of these devices can often be traced to the demonstration apparatus devised by and made by Hauksbee and Whiston in 18th century London. As the 19th century progressed, small electric motors began to be incorporated in scientific apparatus. Tom describes some of the applications in Small Direct-Current Electric Motors.
- Allan Mills on Colour Matching and Mixing with Particular Reference to Maxwell’s Disc discusses the theory of colour mixing which is divided into additive mixing of coloured lights and subtractive mixing of pigments. He illustrates how the young James Clerk Maxwell attempted to quantify colour nomenclature and additive mixing with his spinning ‘colour disc’, made up of adjustable sectors of the three ‘primary’ colours red, green and blue, plus black or white. Some experimental demonstrations are suggested.
- Deborah Jean Warner on Charles A. Spencer and His Early Microscope Objectives presents evidence from a variety of users that attests to the quality Spencer optical skills. His microscope objectives compared very favorably and often exceeded the resolution of examples made by others. Unfortunately Spencer did not divulge the details of his methods.
Kennith A. Devine on Early Toronto Temperatures provides a table based on almost 7,000 measurements made between 1831 and 1838 in downtown Toronto by Rev. Charles Dade. This becomes the basis for comparison with modern results and provides some cautionary advice for analysis of data sets relevant to climate change calculations.
About Our Authors
Kenneth A. Devine, born in Northern Ontario, joined the Meteorological Service of Canada in the spring of 1971. Initially he worked as an upper air observer and an electronics technician before completing his degree and the meteorologist course. After four years of forecasting on the east coast, Ken joined the MSC’s Instrument Branch in data acquisition positions. Moving from Field Services headquarters, Ken became Superintendent of Climate Data Standards in the Climate Division. Not content to sever his scientific interest on retirement (1998), he continues researching the area of historical meteorological instrumentation. Ken has published over ten articles in the Bulletin of the Canadian Meteorological and Oceanographic Society including “The Accuracy of Canadian Rainfall Measurements”, in 2008.
Thomas Greenslade is the most frequent contributor to eRittenhouse. Tom is a professor emeritus at Kenyon College, Gambier, Ohio and has a personal collection of several hundred instruments. Many have been given to him by physics departments from across the US and he has, without any doubt, visited more university and college collections and written more about them than anyone else. In addition to more than 280 papers, Tom has provided 555 page fillers through August 2016 for the American Journal of Physics based on about 725 pieces of early apparatus in his collection, ones he has used, or that are special in the history of the discipline. Tom is a Fellow of both the American Physical Society and the American Association of Physics Teachers.
Allan Mills retired 18 years ago from the post of senior lecturer in the Department of Physics and Astronomy of the University of Leicester. Although it is difficult to do research in modern science at home, he has found a vast – and largely untapped – field in experimental and practical studies in the history of science.
Deborah Jean Warner was the founding editor of Rittenhouse, the forerunner of eRittenhouse. She continues to be one of the top researchers in the history of scientific instrumentation while continuing her role as curator at the Smithsonian Institution’s National Museum of American History. Her bibliography includes books and articles pertaining to the history of physics and related instruments, women in science, and celestial cartography.