6 4 



HARD WICKE'S SCIENCE- G OS SI P. 



come about. The expense, mischief, and annoyance 

 due to the bursting of water-pipes in a house is a 

 serious tax, and should therefore be appraised as a 

 heavy discount on the rental value of the house. 



The Philosophy of Hair-curling. — According 

 to a contemporary, "it is not generally known that 

 the reason why hair curls when wound on a hot iron, 

 is that the moisture on the side next the iron being 

 evaporated by the heat, the cells in that part approach 

 each other more closely, and this shrinking of one 

 side causes the bend or curve." This explanation 

 affords presumptive evidence that the writer is a 

 young man, or at least young compared with myself. 

 He was not flourishing when I went to the dancing- 

 school, and under the mandate of imperative custom 

 had to go to the hair-dresser before presenting myself 

 at the "assembly-room." They did not enforce hair 

 curling on " breaking-up " day at his school as at the 

 "Academy for Young Gentlemen" where I was 

 taught to regard all books as instruments of torture, 

 and to hate them accordingly. Had he endured 

 such experience he would have known that each 

 particular hair was doubly or trebly twisted, and on 

 completion of the twisting a comb was inserted 

 between the curl and the scalp, and the hot tongs 

 held for some time with the twisted hair in position, 

 quite long enough for the heat to freely pass through 

 a hair's breadth. The force of the final twist which 

 I so painfully remember was a result of the operator's 

 belief, founded on much experience, that the whole 

 operation depended upon a certain degree of mere 

 mechanical rigidity of the material operated upon 

 which induced it to retain for a time any form into 

 which it was forcibly restrained and maintained while 

 hot. The recondite explanation above quoted does 

 not cover the action of cold curl papers. 



The Mutability of Species. — In the Transac- 

 tions of the Manchester Microscopical Society of last 

 year is narrated (in the President's Address) an 

 interesting account of change of species. In the 

 neighbourhood of the Black Sea were a couple of 

 lakes separated by a dam. The larger and higher of 

 these contained 4 per cent, of salts, and in it Artcmia 

 salina were living there in great quantity. The 

 smaller and lower lake held in solution as much as 

 25 per cent, of salt and contained no artemioe. 

 The dam between the two lakes was accidentally 

 burst in 187 1, the lower lake was thereby greatly 

 increased in size, and its salinity reduced to about 

 S per cent. Many of the artemia; carried down 

 with it died and many survived. The lower lake 

 now began to evaporate, and the strength of the 

 solution to increase. In the summer of 1872 the 

 salinity had risen to 14 per cent., in the summer of 

 1873 to 18 per cent., in August 1874 to 23J per cent., 

 and in September of the same year to 25 per cent. 

 A Russian naturalist, Schmankewitsch, fished out 



and examined specimens of the artemia? at intervals 

 during the three years, and found that as the strength 

 of the solution increased, the artemise gradually lost 

 the specific characters of Artemia salina and acquired 

 those of Artemia Miilhauseni. The tail lobes gradually 

 became shorter, and the number of setse diminished, 

 until at the end of the third year all the artemiae were 

 converted into typical Artemia Mulhauseni. The 

 reverse experiment has been performed artificially. 

 By gradually diluting the water Artemia Mulhauseni 

 were reconverted into Artemia salina, and, by pushing 

 the dilution still further, not merely a specific, but a 

 generic change has been effected, the latter being 

 converted into the fresh-water genus Branchipus which 

 is of larger size and in many respects different. 



I remember well when the immutability of species 

 was a sacred dogma, one of the articles of faith of 

 the orthodox naturalist. I had some warm debates 

 on the subject just after the publication of "The 

 Vestiges." If an instance like the above was brought 

 forward and could not be denied, the whole fabric 

 of previous specific definition was abandoned, and 

 the new species was described as a "variety." One 

 such instance which I remember was that of our 

 common wheat, which was shown to be derived from 

 another genus. Accordingly generic definition was 

 abandoned and specific differences bounded over in a 

 wide leap, the two genera were converted into mere 

 varieties. Thus the controversy became closed by 

 the verbal device of defining a species as that which 

 cannot be changed into another species, ergo species 

 are immutable. 



What extraordinary change has since occurred 

 among naturalists ! They themselves are no longer 

 of the same species as formerly, and have even 

 changed their generic name to that of " biologists." 

 In contemplating this example of scientific evolution, 

 let us not lose sight of the moral it conveys. Let us 

 struggle to avoid all scientific dogmatism, and to fre- 

 ourselves from the fetters of mere fashion in science, 

 or what I have ventured, very impertinently, to 

 describe as " scientific millinery." 



ASTRONOMY AND METEOROLOGY. 

 By John Browning, F.R.A.S. 



AT the meeting of the Royal Astronomical Society, 

 held on the 13th of January, Father Perry 

 read a paper on the state of the solar surface during the 

 year 1887, and gave an account of observations which 

 he had made on 259 days at the Observatory of 

 Stonyhurst. The number of days he had been able 

 to observe the sun proved that the weather had been 

 exceedingly fine in that part of England. 



From January to April, 1SS6, the solar surface was 

 free from sun-spots ; but at the beginning of May, 



