564 



NATURE 



\Oct. 28, 1875 



half the former amount of water ; the stock now consumes the 

 reeds and marsh-grass, exposi'.ig the water to the direct rays of 

 the sun, thereby promoting evaporation, so that by midsummer 

 even the mud in their basins has dried to a hard crust, and a 

 change in the temperature during the heated term brings, as a 

 rule, a cool, dry atmosphere instead of rain, as in former years. 

 Mr. Sawyer goes on to describe the large increase in the con- 

 sumption of water by domestic animals. In this State at the 

 present time there are at least "three million horses, cattle, and 

 mules, and five million hogs and sheep, and they will consume 

 not less than seventy million gallons of water every twenty-four 

 hours— quite a lake of itself." This, surely, must be a misprint, 

 or American animals are very thirsty beings ! 



A CORRESPONDENT of . the Aberyshvith Obso-ver, the Rev. 

 James Lewis, of Llanilar Vicarage, writes as follows to that 

 journal : — " Whilst returning from service at the parish church of 

 Rhostie, about 8.15 p.m. on Friday, the 24th ult., in company 

 with two members of the congregation, my attention was called 

 to a remarkably strange phenomenon. In walking across a field 

 on the farm of Cwmclyd, it was noticed that our footsteps were 

 marked by a peculiar light, which could be traced back for 

 several yards, each footprint being as distinctly marked on the 

 ground as when one walks in snow. When we got into the 

 adjoining field the light disappeared until we came near to the 

 end of it, when it was observed that our footsteps were again 

 marked by the; same luminous appearance. In colour the light 

 was similar Jo that of phosphorus rubbed on a wall in a dark 

 room, or a mass of glow-worms, of which insect, however, there 

 was no trace on the surrounding ground." 



In the Bulletin International of the Paris Observatory for the 

 2ist inst. appears an interesting note by M. de Lagrene on the 

 thunderstorms which have occurred in the department of Haute- 

 Marne during the seven years ending 1874. In this department 

 the average annual number of thunderstorms is 87, of which 25 

 occur in July, 20 in May, and 14 in June. During the six 

 months from October to March inclusive the mean.'annual aggre- 

 gate is only six. The geographical position of Haute-Marne is 

 an important one as regards these electrical phenomena, about 

 which so very little is yet known, and this Departmental Meteo- 

 rological Commission is doing good service in contributing its 

 share in the work of collecting data on the origination, intensity, 

 and rate of propagation of thunderstorms, and the manner in 

 which they are influenced by the winds prevailing at the time, by 

 the contour of the ground, and by forests. 



We have received the first number of the Iowa Weather 

 Review, September 1875 (PP- 20), which has just been started 

 by Dr. Gustavus Hinrichs, from which we learn that the system 

 of rain ob:,ervations set on foot by him, as explained in a recent 

 notice in Nature, is only the beginning of a more complete 

 system by which it is hoped that the whole meteorology of this 

 important State will be adequately and systematically observed 

 and turned to practical account in the interests of the people. 

 There is an idea shadowed out in the prospectus by which, if 

 gone into and developed, the United States will be divided into 

 meteorological districts or regions similar to what is now being 

 done in France, and which is really the only means by which 

 many highly important questions can be properly investigated. 

 Dr. Hinrichs gives the monthly rainfall for the months of past 

 years' observations, as well as the monthly means, at six places 

 in the State, and sends a carefully compiled monthly report of 

 his own observations made at the laboratory of the Iowa State 

 University at Iowa City, the amounts and averages of each 

 month being compared with the results of previous years' 

 observations. 



The additions to the Zoological Society's Gardens during the 

 past week include a Binturong (Arctictis binturong) from Malacca, 



presented by Captain A. R. Ord ; a Wood Owl {Syrnium aluco), 

 European, presented by Mr. F. Brannd ; a Missel Thrush 

 {Turdus viscivortts), European, presented by Mrs. Watson; a 

 Grey Wagtail {Motacilla boarula), seven Picked Dog Fish 

 {Acanthias vulgaris), European, purchased ; a Cape Buffalo 

 (Bubalus caffer) born in the Gardens. 



ON THE VARIATIONS OF THE ELECTRO- 

 MOTIVE FORCE OF A NEW FORM OF 

 LECLANCHt'S CELL 



A NEW form of Leclanche's cell has been constructed by Dr. 

 -'"*■ Muirhead, and is supplied by Messrs. Warden, Muirhead, 

 and Clark. 



In this form the carbon and black oxide of mangane-e are 

 packed in the outer case around a glazed porcelain jar perforated 

 with holes about one-eighth of an inch in diameter, the jar con- 

 taining a zinc plate bent into the form of a cylinder. 



The advantages gained are that a much larger surface of zinc 

 is exposed and the perforations of the jar are in no danger of 

 being choked up by deposition of chloride of zinc. 



The following results may be of some interest as showing how 

 the electromotive force of this cell varies when it works for a 

 considerable time through circuits of various resistances. 



A circuit of known resistance was formed, through which the 

 battery worked, and two points in this circuit were attached to 

 the poles of a sawdust Daniell's cell, so as to form a branch cir- 

 cuit in which a galvanometer was included ; one of these two 

 points was then moved along the circuit until the galvanometer 

 showed that there was no current through the Daniell ; when 

 this is the case the E.M.F. of the battery is to that of the Daniell 

 in the same ratio as the resibtance of the whole circuit to that of 

 the part between the points of attachment of the Daniell. 



A set of coils was used by which the resistance could be 

 adjusted to '05 ohm, and by adding one of these coils to the 

 common part of the circuit (so that the resistance of the whole 

 circuit did not remain quite constant) a very small change in 

 E.M.F. could be measured. 



The current through the Daniell was always very small, and 

 as it passed sometimes in one direction and sometimes in the 

 other, the difference between the potentials of its poles must have 

 remained very nearly constant. 



In the circuits of small resistance it became necessary to take 

 account of the internal resistance of the cell. This was found 

 (for these circuits) to be generally between '45 and -46 , it was 

 subject to slight variations between these limits, but rarely 

 exceeded them when the battery was worked for only two cr 

 three hours, although on leaving the battery circuited through 

 30 ohms for 20 hours it rose as high as '525. The lowest 

 rcbistance observed was '420 when working through 10 ohms. 



The following tables give the E.M.F. ot the battery in terms 

 of the Daniell :— 



When the cell had been circuited through 10 ohms for 



2 min., the E.M.F. was i'320 ; for 3| min., I*3I4 ; for 5^ min., 

 I '304; for 13 min., i"292; for 23 min., I '283; for 34 min., 

 1-277. For ih. im., 1-266; for ih. 31m., 1*256 ; for ih. 56m., 

 1*254; for 2h. Iim., 1-253. 



When circuited through 20 ohms lor 2^ min. the E.M.F. was 

 I -3465 ; for 4 min., I -3420 ; for 54 min., 1-3385 ; for 13 min., 

 I "3315; for 18 min., 1-3270; for 30 min., 1-3215 ; for 46 min., 

 1*3155. For ih. im., i'3095; for ih. 22m., 1*3045; for ih. 

 31m., 1-3035. 



When circuited through 30 ohms for \ min. the E. M. F. was 

 I -3702; for 2 min., 1-3608; for 3 min., 1-3585; for 4 min., 

 I -3562 ; for 10 min., 1-3500 ; for 20 min., i -3446 ; for 26 min., 

 1-3404; for 28 min., I -3391. For the next four minutes the 

 E.M.F. was very unsteady. For 32 min., 1-3411 ; for 33 min., 

 I "3398 ; for 39 min., i -3364. For ih. 3m., i -3318 ; for lii. 14m., 

 1*3292; for Ih. 28m., 1*3211 ; for 23h. 30m., 1-2810. 



When circuited through 100 ohms for 7 min. the E.M.F. was 

 I -4415 ; for 10 min., 1-4417 ; for 20 min., 1-4423. 



No further change was observed at the expiration of one hour. 



When the cell (after being insulated for 21 hours) was circuited 

 through 3,200 ohms, after i min. the E.M.F. was 1-448; after 



3 min., 1-450 ; after 18 min., 1*454; after 38 min., 1-459. 

 When the cell was short circuited through itself for two 



minutes tne E.M.F. fell from 1-407 to 1-235. (These measure- 

 ments were taken with the cell working througlr 3,500 ohms.) 



