XXXII.—A simple thermostat for use in connection with the refractometric examination of oils and fats
Journal of the Chemical Society Transactions
IN the Government Laboratory, as in other laboratories where large numbers of commercial oils and fats, and especially butter, are required to be examined, the Zeiss butjro-refractometer has proved to be of great service. As is well known, it is generally necessary in using the instrument t o allow a current of water of conytant temperature to flow through the apparatus for some little time before making the readings, and it mas with the view oE rapidly and easily obtaining this current that
... his current that the little contrivance seen in the accompanying figure was devised in substitution for the special heating arrangement supplied with the instrument, which was found to be homewhat cumbrous and uncertain in action. The temperature employed in the refractometric examination of butter-fat is 45', and it must be understood, therefore, that the details of the arrangement as described have been adjusted in order that the circulating water shall give this temperature as indicated by the thermometer attached to the refractometer. It is, however, possible, by a slight rearrangement of the details, to obtain a considerable range of constant temperatures. The principle of the thermostat and the method of working it will be obvious from the figure. The apparatus consists essentially of a vessel for generating steam or other appropriate vapour, containing a coil through which the current of water flows and is heated before it passes through the refractometer or other instrument, the position of which is shown in the drawing a t Z, by which the observations at a given constant temperature are to be made.