VI. Underground temperature at Oxford in the Year 1899, as determined by five platinum-resistance thermometers

The instruments with which the earth-temperatures given in this paper were observed, were five platinum-resistance thermometers of the Callendar and Griffiths pattern, made by the Cambridge Scientific Instrument Company. These were purchased by the late Mr. Stone, and were placed in position under his direction shortly before his death. The method of platinum thermometry seemed to be particularly suitable for this class of work, on account of the immunity it enjoys from certain errors attending the use of the long-stemmed mercurial or spirit thermometers ordinarily employed for underground temperatures.