378 



SCIENCE. 



[Vol. VIII., No. 194 



the facts of nature reaUy are as here represented, 

 the gaining of this new point of view must be 

 regarded as a distinct advance in this adaptation. 

 From the above unsatisfactory ' sketch of Pro- 

 fessor Mach's position, it may perhaps be seen that 

 he regards a great psychophysic movement in 

 science as the next revolutionary process. Many 

 signs of such a movement are ah-eady evident, 



J. J. 



A MANUAL OF NORTH AMERICAN BUT- 

 TERFLIES. 



Although a really good manual of our but- 

 terflies has long been a desideratum, Morris's 

 Synopsis being altogether out of date, it cannot 

 be said to be supplied in the present work. 



The whole aim of the author seems to be to 

 enable his reader to find out the name of a speci- 

 men in hand ; and to this end his ' analytical 

 key' is fairly good, so far as the perfect insect 

 goes, excepting, that as no tables are given for 

 genera, families, etc.. it would not help the stu- 

 dent if species not included in the book were to 

 turn up. The key is also faulty, because largely 

 made up of very unimportant characters, and 

 because it takes no account of the earlier stages ; 

 indeed, no means whatever ai'e anywhere fur- 

 nished for finding out the afifinities of a caterpillar 

 or chrysalis in hand, except by wading through 

 all the descriptions in the book. 



We fail to see how the work can be of any 

 possible pedagogical service, although this is 

 claimed as its chief end. For, first, the only clew 

 it gives to the classification, i.e., the natural ar- 

 rangement of butterflies, is in the brief state- 

 ment that is presented of the characters of 

 some of the higher groups, and, incidentally, in 

 the actual arrangement of the species treated ; 

 there is scarcely a reason siiggested why the 

 sequence of the groups should be as it is ; it is 

 simply stated in the preface that Edwards's ar- 

 rangement is followed, yet Edwards has never 

 offered a reason, but only printed a bare list. 

 Second, the arrangement itself is unnatural, hold- 

 ing its ground only through precedent, as a legacy 

 from the less-informed authors of fifty years ago. 

 Third, the whole aim of the author appears to be 

 to enable the user to answer the question, ' What 

 is the name of my butterfly ? ' — for pedagogical 

 purposes not even a worthy, far less the best end. 



The genera are nowhere characterized ; the 



1 The account is perhaps unavoidably so ; as it was the 

 task of tbe reviewer to avoid the technicalities of the psy- 

 chological part on one side, and of the physical part on the 

 otner. 



The butterflies of the eastern United States, for the use 

 of classes in zoology and private students. By G. H . French. 

 Philadelphia, Lippincott, 1886. 12°. 



descriptions of the butterflies could be much im- 

 proved by more concise and methodical expres- 

 sion and the italicizing of the most distinctive 

 features ; the early stages of a considerable num- 

 ber of species are omitted, when they have been 

 known and published for many years ; and, 

 finally, there is not a line or suggestion tlirough- 

 out the book which would lead one to suspect that 

 science had changed w^ithin the last eventful 

 quarter-century. It is but the rehabilitation of 

 the dry husks of a past generation. 



SCRANTON is the centre of what is known as 

 the northern anthracite coal-field of Pennsylvania, 

 comprising nearly two hundred square miles. 

 Using this fact as a fulcrum, and taking for a 

 lever the fact that natural gas has to a great ex- 

 tent displaced coal in Pittsburgh, the Scranton 

 board of trade are endeavoring to lift their home 

 into prominence as one of the gi-eat manufactur- 

 ing cities of the fut\u-e. In a neat pamphlet 

 recently published by the board, it is pointed out 

 that gas is a more economical fuel than coal ; 

 that the supply of natural gas will soon be ex- 

 hausted ; that there are forty miUion tons of culm, 

 or coal-waste, — which may be had for the tak- 

 ing, — lying about the mines of the Scranton 

 region ; that this amount is being increased by 

 two million tons annually ; that gas may be made 

 from this waste at a cost of tvi^o cents per thou- 

 sand feet ; that in the near future coal will prob- 

 ably^be converted into gas in the mines, and piped 

 to the surface ; that gas-engines are steadily grow- 

 ing in favor ; and that Scranton is already a great 

 railway centre, with excellent shipping facilities 

 to aU i^oints of the compass. The conclusion is 

 inevitable, at least to the publishers of the pam- 

 phlet, that Scranton is a very desirable place for 

 the establishment of industries requiring cheap 

 fuel and power. 



— An experiment with a new hydro-carbon 

 fuel burner for locomotives was recently tried on 

 the Thu'd Avenue elevated railroad in this city. 

 The burner is about six inches in length by five in 

 diameter. A spray of petroleum and steam was 

 forced through perforations in the burner, pro- 

 ducing a large volume of flame ; but, through in- 

 ability to control the draught of the furnace, 

 combustion was imperfect, and the experiment 

 was a failure. This was only one of a long 

 series of experiments with similar devices, none 

 of which has succeeded. As the consumption of 

 coal on the locomotives of the elevated railroads 

 averages only two and six-tenths pounds per 

 horse-power developed, there would seem to be no 

 field for the economic substitution of petroleum 

 at present prices. 



