Glass Thermometer Research Articles

A New Disposable Oral Thermometer in Clinical Use

It has become accepted practice in patient evaluation that the sublingual estimation of temperature is an accurate guide to the patient’s systemic temperature. If we are to rely upon this for the diagnosis and management, we must be assured of accuracy. Furthermore, the estimation of the patient’s temperature consumes a fairly large amount of nursing time. Therefore, improvements in accuracy, and reduction of time would be valuable and important additions to our armamentarium. We feel that both of these and other significant attributes are available in an entirely new method of thermometry. We are going to describe this method and assess its usefulness in comparison with the clinical glass thermometer.

Psychrometers with liquid in glass thermometers

Psychrometers with liquid in glass thermometers

Liquid Thermometer Recorder

The recording liquid thermometer described below was designed primarily to record the water temperature in the field with an accuracy of 0.05°C or less.Cook, L.O., in 1940, designed a similar recorder, in which the record was obtained by casting the shadow of a flat section mercury column of a glass thermometer on to bromide paper. The shadow casting method, however, is not so good for precision recording, because light fluxes passes through the vacuous column of the glass thermometer are dispersed and do not make distinctive contrast against the shadow of the mercury column.Instead of mercury, the present author utilizes a transparent liquid with the suitable coefficient of expansion and refractive index μ. The value of μ is decided as it makes the glass tube with the liquid column a thick lens, which has a proper focus length.The instrument consists of four parts; a liquid thermometer, a drum carrying the bromide paper, a light source and multiflex mirrors, and a constant clock. The thermometer has a round section liquid column and an accurately graduated scale and its bulb is courted with black lacquer or covered by a thin-walled tube to cut off light penetration into the thermometer. Light from a 4V point-source lamp reaches the thermometer through a slit after reflecting between two mirrors and with full path of 75cm.A constant clock has two functions; driving the drum carrying the bromide paper and operating the light switch intermittently.Specimen records are shown with the vertical lines making the time, and the horizontal lines half degree with the heavy line at 10°C as an index.

Temperature Changes in Gastrointestinal Tract in Relation to Heat and Cold on Skin

For our temperature readings of a mucous membrane of gastrointestinal tract we used a Queen's potentiometer. Ten dogs were used. Under nembutal anesthesia, the abdomen was opened and an opening in the stomach or intestine was made. For measurements of temperature of mucous membrane of the stomach the ends of 3 thermocouples (devised by Bachem), covered with shellac and embedded in celloidin, were introduced into the stomach and fastened to the inner surface by a ligature. For recording the temperature of the mucous membrane of the intestine the 3 thermocouples mounted on a piece of a rubber tubing of suitable diameter, and fastened with a rubber band were introduced into the intestine (duodenum). For measuring the temperature of the rectum the thermocouples were introduced through the anus. Heparin was injected intravenously (10 mg. per kilo), the femoral artery opened and a long glass thermometer introduced through it into the abdominal aorta. Ice packs and hot moist towels were applied to the skin of the chest of dogs. The results are shown on the accompanying graphs. The abscissa represents the time from the beginning of the experiment, the ordinates—temperature in centigrade. Dotted lines represent the findings of the temperature in the abdominal aorta, the straight line—the temperature of the surface of the mucous membranes. The perpendicular lines show the time of application of cold and heat to the body surface of the dog.

Temperature Changes in the Liver in Relation to Heat and Cold on Skin

For recording the temperature in the liver we used a fever recorder of Siemens and Halske. To this apparatus were devised special electrodes of a size suitable to requirements of the case, made of a piece of flat mica wound around by an iron wire of a diameter of 0.00175 in. The electrodes were insulated on one side by cork and mica and on the other side (sensitive part) with shellac and celluloid. Both ends of a wire were attached to heavier wires, connected with the galvanometer and the latter with the fever recorder.Six dogs were used. Under nembutal anesthesia, the abdomen was opened and the flat electrode placed between the lobes of the liver, fastened by its wires to the external surface of the abdominal wall by means of an adhesive plaster and the abdomen closed. Heparin was injected intravenously (0.01 per kilo), the femoral artery opened and a long glass thermometer introduced through it into the abdominal aorta. Ice packs and hot moist towels were applied to the skin of the chest of dogs.The res...

The Construction of Standard Thermometers

A series of important articles on the preparation and testing of standard thermometers have been communicated to the Zeitschrift für Instrtimentenkunde by Drs. Fernet, Jaeger, and Gumlich, of the Physikalisch-Technische Reichsanstalt. The selection of the best glass, the calibration of the thermometers, the determination of the coefficients of external and internal pressure, and the verification of the principal points are fully dealt with. One source of error in thermometers as usually constructed, lies in the fact of the bulbs being blown from the tubes. The vaporisation of certain constituents of the glass during this operation leads to a difference of chemical constitution between the stem and the bulb. This may be obviated by making the bulbs out of thin walled tubes of the same kind of glass, and welding them on to the stems. As regards the depression of the freezing point, it was found by Wiebe and Schott, of Jena, that glasses containing either sodium or potassium, but not both, showed this after-effect to the least extent. In order to render the reading of temperatures accurate to within O°˙'OO2, the length of a degree should not be less than 6 mm., and since the length of the stem cannot conveniently exceed 60 cm., the range of measurable temperature is practically limited to 100°. Stem thermometers without enamel backs or enclosing tubes were the only ones found suitable for first-class standards. When certain fixed points outside the scale were to be brought in, this was accomplished by widening out the tube above them. An equal linear division of the scale was adopted, this having great advantages over the more or less untrustworthy division by equal volumes. For calibration, threads of mercury of different lengths were cut off from the main portion and measured with micrometer microscopes, viewing them both through the face and the back of the stem. But the threads were not cut off by local heating, since that is apt to produce a permanent change of capacity. The small and almost microscopic bubble which remains in every thermometer was made use of. It was brought to the entrance of the bulb when the desired portion of the thread had been driven into the stem, and then a slight jerk sufficed to cut off the required length. To facilitate this operation, the bulb was narrowed to a neck at the entrance to the stem. As regards pressure, two factors had to be considered. The external atmospheric pressure, and the pressure of the liquid in which it is immersed, tend to compress the glass vessel and to produce an apparent elevation of temperature. The capillary pressure of the mercury, and its hydrostatic pressure, on the other hand, tend to widen the bulb and produce an apparent cooling. The first of these elements was investigated by exposing the thermometer to various high and low pressures in a glycerine bath, and the second by observing the readings when the thermometer stood horizontally and vertically respectively, at its highest measurable temperature. The capillary pressure was found to be too capricious to be accurately measured, but it is a negligible quantity. The coefficient of apparent expansion of mercury in the new Jena glass thermometer 16m was found to be 0˙0001571 between 0° and 100°.