144 



SCIENCE. 



[Vol. V., No. 107. 



But there still remains to be found the actual 

 mechanism of thunder-storms, concerning 

 which various more or less theoretical opinions 

 have been published. The matter will prob- 

 abty remain in doubt until settled by the 

 same kind of investigation that demonstrated 

 the inward spiral path of cyclonic winds. 

 Synoptic charts for a stormy afternoon, with 

 hourly or even half-hourly intervals, and sta- 

 tions only a mile or two apart, would probably 

 settle the question beyond dispute ; and the 

 first local weather service that succeeds in 

 preparing a set of such charts will gain a prize 

 worth working for. 



LETTERS TO THE EDITOR. 



*** Correspondents are requested to be as brief as possible. The 

 writer's name is in all cases required as proof of good faith. 



The incandescent light on steamers. 



The instance cited in No. 104 of Science, of early 

 electric lighting. of steamboats by the incandescent 

 system, though earlier than that given by Professor 

 Trowbridge, is not the earliest. 



I crossed the Atlantic in May, 1882, in the steamer 

 City of Richmond, of the In man line, which was 

 beautifully lighted by the incandescent system. It 

 is my impression that the lamps were of an English 

 make, the form of the carbon filament being some- 

 what different from that then used by Edison and 

 other Americans. C. H. Ames. 



Chopping-stones. 



It is not improbable that the implement figured in 

 a recent article by Miss Babbitt (iv. 529, fig. 3) could 

 have been used as a fuel-breaker, when fastened in a 

 wooden and hide handle; but a more evident use for 

 such notched pebbles, namely, as net-weights, is seen 

 in an industry of the present day among the gill-net 

 fishers, both Indian and white, of the Great Lakes. 

 Net-weights of this character are produced in large 

 quantities at all points on the lakes where gill-netting 

 is in vogue, forming frequently a part of the ballast 

 in the bottoms of the ' Mackinaw' fishing-boats, and 

 lying conspicuously scattered over the sand and beach 

 in the neighborhood of fishing-stations. A less 

 primitive appliance for sinking the nets is coming into 

 use; so that the notched discoiclal pebbles, attached 

 to the net with short pieces of twine, are now re- 

 garded as old-fashioned by the more thrifty fishermen. 

 The unnotched pebble net-weights, bound with bark, 

 of the Red-Lakers, are interesting as a still more 

 primitive form; but more extended observation in 

 gill-net appliances would have shown Miss Babbitt 

 that the notched form is of far more usual occurrence 

 than she leads us to suppose, and that it possesses 

 tons of examples on the shores of the Great Lakes. 



I have found such implements associated with the 

 remains of recent Indians (chert chippings, broken 

 pottery, etc. ) in the sand-dunes at Evanston. The 

 modern net-weights are distinguishable from those of 

 the chert deposits in only one particular, that while 

 the surfaces of the former are smooth, and their 



notches rough and angular, those of the latter show 

 on their surfaces the effects of disintegration from 

 long exposure on the sand to atmospheric agencies, 

 their notches, too, having assumed the same crumbling 

 character as the rest of the pebble. A large number 

 of them (over twelve) which came to my notice at 

 one place indicates their use as net-weights rather 

 than as ' chopping-stones.' W. A. Phillips. 



Evanston, 111. 



The use of slips in scientific correspondence. 



I have been interested in Mr. Mann's and other 

 articles on filing scientific notes. 



Any one wishing to file such notes will find that a 

 very convenient method of doing so is by the use of 

 the Shannon file, which may be found at any large 

 stationery store. The punch for punching the holes 

 through the paper is the most convenient I have 

 seen, as the holes are always the same distance 

 apart, and at the same distance from the edge. 



S. P. Sharples. 



The decadence of science about Boston. 



In a late issue (No. 104), Science comments upon 

 the decadence of science about Boston. Is it not an 

 explanation of this decadence that more and more in 

 late years the mental atmosphere of Boston has be- 

 come one of intellectual finish, rather than of intel- 

 lectual earnestness? Of course, each of these traits 

 has its excellences, as each may be exaggerated ; but 

 the latter of the two certainly is far more favorable 

 to the active growth of science in a community. 

 Moreover, the effect of an intellectual atmosphere 

 becomes most evident when it has begun to influence 

 the lives of young men grown up in its midst, and 

 who take their cue in life from it. Is not this effect 

 to be noticed in the present case ? X. C. 



Koch's 'comma bacillus.' 



In the reproduction of the drawing of the 'comma 

 bacillus,' made to illustrate my paper in Science for 

 Feb. 6, some defects are noticeable, to which it seems 

 necessary to call attention, inasmuch as the design 

 was to represent as accurately as possible the mor- 

 phology of this much-talked-of micro-organism. The 

 ends of some of the commas in the figure seem to 

 be cut off square, whereas in the slide and in the 

 drawing they are all rounded. Since writing the pa- 

 per referred to, I have been favored by Dr. Koch with 

 a slide of the ' comma bacillus,' in which the long 

 spiral forms are far more numerous than in the slide 

 sent to the Army medical museum, from which the 

 drawing was made. Several of these spiral filaments 

 are often seen in a single field, and many of them are 

 longer than that seen in the centre of fig. 1. 



Geo. M. Sternberg, surgeon U.S.A. 



Johns Hopkins university, Baltimore, 

 Feb. 11. 



Carnivorous habits of the muskrat. 



My observations of these animals were conducted 

 principally along the banks of the Alleghany River 

 in the vicinity of Warren, Penn., where these enemies 

 of fresh-water bivalves are very numerous. 



1°. The muskrat opens the shell by first severing 

 the posterior adductor muscle. This can readily be 

 accomplished, as the animal seldom immediately 

 empties the branchial chamber after capture, but re- 

 mains with the valves slightly gaping, with the siphons 

 open, until it receives quite severe handling, upon 

 which the water in the branchial chamber is violently 

 ejected. The valves will also partially open if the 



