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18S5 



told him that in their youth, fifty years since, they frequently 

 noticed, when at toilet, that the reflection of the sun from the 

 mirror on the wall or ceiling contained the figures or letters on 

 its back. It is said to have been known to the Romans in con- 

 nection with some of their mirrors, and any one concealing a 

 mirror possessing this quality was arrested as a sorcerer ; but the 

 authority for this statement is not given. The subject is 

 engaging considerable attention, as will be seen from the fact 

 that in recent years a list of fourteen writers on the subject is 

 quoted, from Stanislas Julien, in 1847, to Messrs. Ayrton and 

 Perry quite lately ; and, as the subsequent discussion showed, 

 there are omissions even in this list. These writers, especially 

 the two latter, have demonstrated beyond doubt that unequal 

 convexities in the mirror beget its magical quality. The polished 

 surfaces are convex, but the convexity is not continuous, and is 

 broken in certain places. After going over what had already 

 been done on the subject, and its results, the author described 

 his own investigations. The riddles of the mirror are far from 

 being all answered by the discovery of unequal convexity. For 

 example, how is the inequality caused — by pressure, heat, or by 

 changes in the molecular tension of the metal plates ? The writer 

 tried many experiments to answer the question, and he succeeded 

 by means of chemical agents in drawing lines on the flat back of 

 a mirror, which were reproduced on a reflected image from the 

 front. His results are : That the irregularity in the convexity is 

 caused by the grinding, which alters the molecular tension, that 

 the magic mirror may be produced at will (it was generally sup- 

 posed to be the work of chance alone), and that the magical 

 quality attributed to it is not confined to Japanese bronze, but is 

 common to all firm, elastic substances. A curious process em- 

 ployed by mirror-workers is describe! by Dr. Muraoka : it 

 appears to be one of the secrets of the craft. If the surface of a 

 mirror has been made concave by mechanical pressure, the injury 

 is not repaired, as might be expected, by hammering the other 

 side, or otherwise forcing the metal back into its place. 'I he 

 workman takes an iron tool with rounded, but slightly rough, 

 top, and rubs the concave portion of the mirror in all directions, 

 until a fine network of scratches has been formed. The place 

 then rises of itself, and, instead of being concave, becomes more 

 convex than the rest of the surface. This convexity is then 

 shaved awaywith a knife made for the purpose, until it becomes 

 even with the rest of the mirror. When this is done the whole 

 surface is again ground, polished, and amalgamated. 



A strange Japanese custom has, according to the Japan 

 Mail, been brought to light by the working of the conscription 

 law. The head of a certain family was instructed that the time 

 had come for his son, whose name was on tin census list, to 

 undergo medical examination prior to actual enlistment. The 

 father lost no time in informing the authorities that the indi- 

 vidual referred to, though bearing a male name, m. his 

 daughter. He explained that having lost two daughters, both 

 about one year old, he had been driven to this expedient to 

 keep the third alive. It appears, further, that in many districts 

 of Japan people still resort, in their anxiety to prolong the lives 

 of their children, to the custom of bestowing upon their offsprings 

 names ordinarily given to infants of the opposite sex, whenever 

 death has made frequent visits to their households. The present 

 case occurred in the capital. 



Ax important memoir by Lieut. Casey on the North American 

 species of beetles of the sub-family Stenini has just been pub- 

 lished. It extends to over 200 octavo pages, and describes in 

 minute detail nearly 170 species, of which the greater part are 

 new, and should form one of the most important contributions 

 to systematic entomology in the States that have appeared. 

 " Stenus," in the broad sense, is well defined as a whole, but is 

 notoi ittsly difficul! in detail. When genera become unwieldy 



owing to the mass of species included, it is a convenience to 

 students if they can be split up by recognisable divisional cha- 

 racters. Acting on this idea, Casey has split " S/eiius" into 

 Stenus and Arms, on tarsal structure. This subdivision eqaally 

 affects European (and even British) species. 



Mr. Alderman W. H. Bailey, as President of the Man- 

 chester Society of Engineers, gave an interesting inaugural 

 address on the 10th inst., his subject being "The Reign of 

 Law in Relation to the Unification of Engineering Work. 1 ' 

 "The reign of law." Mr. Bailey stated, "is imperial in the 

 domain of the engineer. He deals with forces which have de- 

 finite, fixed value-. If he perceives a quantity or a force he 

 knows that he can identify the same measure or quantity of the 

 like whenever he meets with its equivalents under equal condi- 

 tions. We know that chance does not rule, and if there be con- 

 ditions that are indefinite or obscure to us it is not because there 

 is no law, but because we are ignorant of its records." This 

 text Mr. Bailey illustrated by reference to the necessity of exact 

 measurement, supporting his position by n 1111 ;rous examples. 



Prof. F. Elgar is about to deliver a special ciurse of 

 evening lectures, in the University of Glasgow, upon "The 

 Buoyancy and Stability of Ships." The course will consist of 

 twelve lectures, commencing on the 22nd inst. These lectures 

 are intended not only for students of this branch of the science 

 of naval architecture, but also for the convenience of draughts 

 men and others who are employed in shipyards during the day, 

 and who are unable to attend the regular University classes. 



In the report of the Meteorological Service of Canada for 

 1884, attention is again called to the advisability of establishing 

 a marine department in connection with the Meteorological Ser- 

 vice for the purpose of organising a system of o^ervations on 

 the ocean by steamers crossing the Atlantic and by those trad- 

 ing with ports in Brazil and the West Indies. Canada, having 

 great shipping interests, should, it is thought, take her part in 

 the great international work now going on of charting the meteoro- 

 logical conditions prevalent over the Atlantic, and in the general 

 development of ocean meteorology. Such observations in the North 

 Atlantic would, it is stated, be of great value, especially in per- 

 fecting knowledge of the movements of a particular class of storms. 

 Recent investigations on the subject of the climatic relations 

 of Canada to European countries show that the Dominion has 

 the latitudes of Italy, France, Germany, Austria, the British 

 Islands, Russia, Sweden, and Norway, and has as many varie- 

 ties of climate as have those countries. There is greater cold in 

 winter in many of the latitudes of Canada than in corresponding 

 latitudes in Europe, but the summers are about the same. The 

 most southern part of Canada is on the same parallel as Rome, 

 Corsica, and the northern part of Spain ; it is farther south than 

 France, Lombardy, Venice, or Genoa. The northern shores of 

 Lake Huron are in the latitude of Central Fiance, and vast 

 territories not yet surveyed lie south of the parallel of the 

 northern shores of Lake Huron, where the climate is favourable 

 for all the great staples of the temperate one. 



Willi the new year Cosmos, the well-known French scientific 

 journal, will enter on a new period. The size will be increased, in 

 order that larger illustrations may be introduced. It will in future 

 c .nsist of 64 columns, two on a page, each of which will contain 

 more matter than its present page. 



The additions to the Zoological Society's Gardens during the 

 past week include a Pig-tailed Monkey {Mac<uus nemestrinus 3 l ) 

 frou Java, a Macaque Monkey (Macacus cy nomoli;us 9) from 

 India, a Vulpine Phalanger {Phalmqista vulpina?) from 

 Australia, presented by Mr. J. Church Dixon ; a Mouflon (Ovis 

 musimon 6) bom Cor.-ica, presented by II.R.H. the Duke of 

 Edinburgh, K.G. ; .< Vul line Phalanjer Pk-ilutpsla vidpina) 



