476 



NATURE 



{April II, 1878 



Monkey {Macacus cynomolgits) from liiSia", presented by Mr. 

 Francis Pym ; a Common Squirrel {Sciurus vtdgaris), European, 

 presented by Madame Hante ; a Vulpine Phalanger [Phalangisia 

 vulpina) from Australia, presented by Capt. F. Ayling ; a Pudu 

 T)Qtx {Cervus Jmmilis), a Naked-eared D&er {Cervus gymnoiis) 

 from Chili, a Maned Goose {Bernicla jubata) from Australia, 

 purchased; an Egyptian Gazelle {Gazdla dorcas) from Egypt, 

 deposited ; a Frazer's Squirrel {Sciurus fmseri) from Ecuador, a 

 Black Sternothere {SternotJuerus niger) from West Africa, 

 received in exchange. 



UNDERGROUND TEMPERA TURE ^ 



/RESERVATIONS on a very elaborate scale have been 

 ^^ received from the important mining district of Schem- 

 nitz, in Hungary. A request for observations was sent by 

 the Secretary, in 1873, to the Imperial School of Forests and 

 Mines at Schemnitz, and on the receipt of two thermometers a 

 Committee was formed to plan and carry out observations. The 

 leading part in the observations has been taken by Dr. Otto 

 Schwartz, Professor of Physics and Mathematics, who hasfur- 

 nished an elaborate report of the results obtained. This is 

 accompanied by a geological report drawn up by Prof. Gustav 

 von Liszkay and by a geological map with plans and sections of 

 the mines. 



The two thermometers sent being deemed insufficient for the 

 numerous observations which were contemplated, twenty-five 

 large thermometers were ordered from a local maker (T. T. 

 Greiner), and the ten best of these, after being minutely com- 

 pared with one of the two thermometers sent — which was non- 

 registering and had a Kew certificate — were devoted to the obser- 

 vations. Three of them were divided to tenths and the others to 

 fifths of a degree Centigrade, and all had bulbs of thick glass to 

 ensure slowness of action. They were found not to change 

 their indications during the time requ'site for an observation. 



The observations were for the most part taken by boring 

 a hole in the rock to a depth in the earlier observations 

 of •422, and in the later ones of 79 of a metre, then filling the 

 hole with water, and after leaving it in some cases for a few 

 hours, in others for several days, to plunge a thermometer to the 

 bottom of the hole, and after thirty or forty-five minutes take it 

 out and read it. The tenths of a degree were read first, and 

 there was time for this to be done before the reading changed. 

 As a rule three observations were taken in each gallery, two of 

 them in bore-holes to give the temperature of the rock, and the 

 third in the air of the gallery at an intermediate position. Pyrites 

 and also decaying timber were avoided as being known to generate 

 heat, and as far as possible currents of air and the neighbourhood 

 of shafts were avoided also. 



A table, which forms part of Dr. Schwartz's report, contains 

 observations made in no fewer than thirty-eight galleries. Besides 

 the temperatures, it gives the depth of the place of observation 

 beneath the shaft-mouth and the height of the latter above sea- 

 level. Dr. Schwartz takes exception to a few of the observations 

 in the table, as being vitiated by the presence of pyrites or by 

 currents of air. 



All the galleries mentioned in the table are classified according 

 to the shafts with which they are connected, and there are for the 

 most part six of these galleries to each shaft. In the final reductions. 

 Dr. Schwartz compares the temperature in the deepest gallery of 

 each shaft with the assumed mean annual temperature of the 

 ground at the shaft-mouth. For determining this latter element 

 the following data are employed. 



The mean temperature of the air at the School of Mines, from 

 twenty years' observation, is 7° '2 C. at the height of 61 2 "6 

 metres above sea-level. The shaft-mouths are at heights of from 

 498 to 763 metres above sea-level, and it is assumed that the 

 temperature of the air falls l° C. for 100 metres of elevation. It 

 is further assumed that the mean temperature one metre deep in 

 the soil is, in these particular localities, 1° C. higher than the 

 mean temperature of the air. The reasons given for this last 

 assumption may be thus summarised : — 



1. Observations in various localities show that in sandy soils 

 the excess in question amounts on the average to about half a 

 degree Centigrade. 



2. In this locality the surface is a compact rock which is highly 



' Report of the British Association Committee on Underground Tem- 

 perature, by Prof. Everett 



heated by the sun in summer and is protected from radiation by 

 a covering of snow in winter ; and the conformation of the hills 

 in the neighbourhood is such as to give protection against the 

 prevailing winds. Hence the excess is probably greater here 

 than in most places, and may fairly be assumed to be double of 

 the above average. 



Omitting one shaft (Franz shaft), in which, owing to the pre- 

 sence of pyrites, the temperatures are abnormal, the following 

 are the principal results :■ — 



The best mode of combining the results from these five shafts 

 is indicated in the last line of the above table, where the sum of 

 the depths is compared with the sum of the increments of tem 

 perature. "We have thus a total increase of 38° '3 C. in 1,587 m. ; 

 which is at the rate of 1° C. in 41 •4m., or 1° F. in 75-5 ieet. 



As these results depend on an assumption regarding the surface- 

 temperature, it seems desirable to check them by a comparison 

 of actual observations, namely, by comparing the deepest with 

 the shallowest observation in each mine. We thus obtain the 

 following results : — 



Combining these results in the same manner as the others, we 

 have a total difference of 26°'3 C. in 1047-3 metres, which is at 

 the rate of 1° C. in 39*8 metres, or i"^ F. in 72-5 feet 



The near agreement of this result vnth that obtained from 

 comparison with the assumed surface-temperature is very satis- 

 factory. The mean of the two would be 1° F. in 74 feet. 



The rocks consist, for the most part, of trachyte and 

 greenstone. 



Dr. Schwartz concludes his report with the suggestion that the 

 heat developed by the decomposition of pyrites and galena in 

 seams which are not altogether air-tight and water-tight, may 

 possibly be utilised as a guide to the whereabouts of metallic 

 lodes ; and that " we shall thus obtain, by means of the 

 thermometer, scientific information which the ancients sought by 

 means of the divining-rod." 



Thanks are due to M. Antoine Pech, Ministerial Councillor, 

 and Director of the Mines, and to Herr Edouard Poschl, 

 Director of the School, for energetic co-operation in this extensive 

 and valuable series of observations. 



Mr. Lebour, having been requested to supplement the above 

 resume of the Schemnitz o'oservations by an account of the con- 

 nection (if any) between the geological and thermal conditions of 

 the several mines, as indicated by a comparison of the reports of 

 Dr. Schwartz, and Prof, von Liszkay, remarks : — 



"The rock at all the mines except Franzschacht is green 



