Practical radiography : a handbook for physicians, surgeons, and other users of X-rays / by A.W. Isenthal and H. Snowden Ward.

  • Isenthal, A. W.
Date:
1901
Catalogue details

Licence: Public Domain Mark

Credit: Practical radiography : a handbook for physicians, surgeons, and other users of X-rays / by A.W. Isenthal and H. Snowden Ward. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    Special Announcement Early in the year 1902 there will be placed on the market a greatly improved io=Inch Spark Portable Induction Coil, Having the following among other advantages:— Output Increased. Weight Reduced. Efficiency Increased. Size Reduced. Insulation Increased. Price Reduced. The Break is almost sparkless, cool to the touch, and adjustable to a nicety. This improved coil is the outcome of over two years' experimental work, during which time upwards of forty test coils have been constructed. The primary and secondary have been mutually adjusted to suit the break. The coil has been proportioned to give a large output with a small accumulator, while a higher voltage can be employed where available. The insulation is exceptionally good, this part of the manufacture occupying nearly a week. The factor of safety is high. Perhaps the greatest merit of the design is that it lends itself to modern methods of manufacture in quantities. Had this not been the case, the numerous improvements introduced would have increased instead of reducing the cost. The efficiency of the ordinary pattern of portable coil has been variously estimated at from five per cent, to ten per cent. This large margin for improvement has been much reduced in the new coil. It is manifest that the output of a coil cannot be definitely and accurately determined in terms of the spark length alone. For the quantity of electricity yielded such expressions as heavy discharge, fat sparks, etc., are too indefinite. An instrument has therefore been devised which gives in milliamperes not only the mean current in the secondary circuit, but also the nature and extent of any oscillation which may exist. See Archives of the Rontgen Ray, August 1901, G. Bowron's Oscillometer. Curves of discharge, measured by this oscillometer, will be supplied with each coil. Coils up to 30-inch spai'k, of small size and great output, are always in progress. 20- inch spark coils, with break and accessories, can now be fitted on bases formerly employed for 10-inch coils. Portable accumulators are a speciality. They are designed for easy inspection, main- tenance, and repair. G. BOWRON, 57 EDGWARE ROAD, LONDON, W.