148 



SCIENCE. 



[Vol. XXII. No. 554 



1. Cost of electricity for cooking as above, - 7.3 cents 



2. Cost of heating water, for jjurjjoses as given 



above, and the same amount, in boiler 

 of fifty j)er cent efficiency, with coal at 

 same price as mentioned above, allow- 

 ing for loss through radiation for day 

 of twelve hours, - - - 1.2 cents 



Total cost. 



8.5 cents 



It will thus be seen that there is practically no differ- 

 ence between electricity and the ordinary cooking stove, 

 so far as cost is concerned, and it is almost needless to 

 point out the advantages of the electric oven over the 

 cooking stove. 



In the first place, we have absolutely no dirt, the elec- 

 trical oven being lined with porcelain enamel, which can 

 be cleaned with the greatest ease. In the second, we 

 have practically no heat outside the oven to heat the 

 room in summer. Then we have absolute regulation of 

 the temperature. If the oven is cold, and we require a 

 temperature of, say, 100 degrees C. to cook something, 

 the automatic regulator is set to 100, and in less than a 

 minute the temperature has risen, and remains exactly at 

 that temperature. Again, if it is desired to only cook for 

 a certain time, say two hours, the cut-out is set for two 

 hours, and at the end of that time the current is either 

 stopped entirely, or is lowered so as to give any reduced 

 temperature that may be desired. 



In conclusion, we may say that the electric oven is 

 bound to come, if only on the score of convenience and 

 accuracy. If cheapness were the only consideration, we 

 should still be burning tallow candles or gas, but people, 

 and especially the American people, vnll always decide in 

 favor of what is most convenient, so long as the diiier- 

 ence in expense is not so great as to form a serious bur- 

 den, and the above data will, it is thought, show that, 

 used in a proper manner, the expense of electrical cook- 

 ing need not be seriously taken into account. 



It will be seen that of every 100 tons of coal used in a 

 cooking stove, ninety-six tons are wasted. It is difficult 

 of course, to get exact figures, but it is probable that the 

 waste in the city of New York alone is not far from 

 1,000,000 tons per annum. 



With the electric stove, though the cost does not 

 greatly differ, yet by far the larger proportion of the ex- 

 pense is due to the labor, interest on plant, and canal- 

 ization, so that (taking the efficiency of the boiler, engine 

 and dynamo as ten per cent) the electrical oven, for the 

 same amount of useful calories, uses only one-fourth as 

 much coal as the cooking stove, and from a social-econ- 

 omical point of view, is much to be preferred, for the 

 more we can live on the world's interest, which is labor, 

 and the less we draw from the world's capital of fuel, the 

 better. E. A. F. 



MOUSE TEAPPING. 



BY FRANK BOLLES, CHOCORtJA, N. H. 



Late in August the mice of our White Mountain woods, 

 fields, and meadows, begin to show an increasing interest 

 in corn, sweet apples, and other kinds of bait usually used 

 in effecting their capture. In the early summer trajaping 

 them is slow work, but the chill of autumn seems to stir 

 them to fresh activity in the gathering of food, and then 

 pursuit of them becomes really interesting. This year I am 

 taking them alive in order to learn more about their hab- 

 its during the winter. Where, in previous years, I have 

 set the deadly little " cyclone " traps, I am now setting 

 the common woven-wire trap with a revolving wheel at- 

 tached. For the ordinary white-footed, or deer mouse 

 {Sitomys americanus), I have only to bait the trap with 



kernels of corn or a bit of sweet apple, and place it at 

 sunset near my wood pile or under the lumber heap back 

 of my barn, and the sound of the whirling wheel is soon 

 heard. For the long-tailed, gray, white-footed mouse 

 {Sitomys americanus canadensis), I go to pine stumps in 

 the woods, or to the old logs on the shore of a pond far 

 from houses, and feel confident of taking him wherever 

 I have previously found traces of his presence. 



It is also easy to capture the short-tailed, brown 

 meadow mouse {Arvicola pennsylvanicus), who always seems 

 to me as much like a diminutive bear as the white-footed 

 mouse is like a tiny deer. His place of abode is readily 

 detected, for he makes long runways in the grass leading 

 to the holes in the ground through which he reaches his 

 burrow. Sometimes I find him under a plank bridge 

 which crosses a moist spot on the edge of the mowing- 

 land, but oftener I trapi him in the long matted meadow 

 grass where his paths lead here and there in search of 

 food or water. As a rule I catch him in broad daylight 

 when he is most active. Emtmys rulilus has a keen eye 

 for protective colors. I find him most frequently in dark, 

 damj) woods, remote from houses, domiciled in hemlock 

 stumps. His chestnut fur matches the color of a decaying 

 stump so closely that he seems like an animated portion 

 of the red wood. He does not, however, confine himself 

 to the forest, for I have caught at least one of his 

 family, close to my barn. Neither does he limit his range 

 to low land, for I have secured specimens a thou- 

 sand feet above his favorite swamps. 



By far the most beautiful of the New England wUd mice 

 is the jumping mouse of the woods (.Zapws insignis). For 

 him I walk back a mile from my house through lonely 

 j)astures and birch woods to a mountain stream which 

 comes sf)lashing over a rocky bed in a dark ravine. It is 

 not on the first, or even the second day, that he conde- 

 scends, or dares, to enter the trap, although that danger- 

 ous engine is carefully covered and disguised with leaves, 

 ferns and bits of growing moss, until it looks like a piece of 

 the wild wood itself. At first he eats the kernels of corn 

 or the pieces of apple which are placed farthest from the 

 trap. Then, night by night, he comes nearer, until at 

 last, having eaten all the corn and apple outside of dan- 

 ger limits, he ventures too far and is caught. Probably 

 Zapus hudsonius, the common jumping mouse, is to be 

 found in this vicinity, but thus far I have not secured 

 him, although his cousin with the white-tipped tail might 

 almost be called abundant. A seventh species, too well 

 known in his customary resorts, is Mus musculus, the old 

 world jjest of the pantry. 



TrajDping mice in " cyclones " often results in supply- 

 ing moles and shrews with food which they seem greatly 

 to enjoy. In fact, Sitomys himself is only too willing to 

 devour the tender portions of his own kindi'ed. Bj using 

 the wheel traja and taking my mice alive, I am not an- 

 noyed by the flesh-eaters. 



SUBMARINE PHOTOGEAPHY. 



BY JOHN HUMPHREY, LONDON, ENGLAND. 



Several of the difficulties experienced in endeavors to 

 ascertain the natural relations of objects existing at con- 

 siderable depths under water have been overcome by M. 

 Louis Boutan, in a remarkably ingenious manner, and the 

 contrivances he adopted are described in a recent com- 

 munication to the Paris Academy of Sciences. 



He prefers to use a smaU. camera in which several 

 plates can be exposed consecutively, and encloses this in 

 a rectangular, water-tight metal box, into the sides of 

 which plates of glass are inserted to serve as windows. 

 The camera can be so disposed that the lens may face all 

 the windows in turn, if desired, and exposures are regu- 



