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POPULAR SCIENCE MONTHLY. 



when another and greater cooling takes place, 

 and is communicated by an ingenious adjust- 

 ment of the machinery to the air that is to 

 be liquefied. The process is repeated, a 

 lower temperature being reached at each 

 repetition, till liquefaction is accomplished, 

 and after this " a continuous stream of liquid 

 air is merely a question of engine power." 

 Further than this, the air during the process 

 becomes steadily richer in oxygen, until that 

 gas forms about seventy per cent of the 

 product, pure enough for most of the pur- 

 poses for which oxygen is used; and we 

 have here a new source for the cheap supply 

 of it. 



The Scientific Alliance. The Scientific 

 Alliance of New York which includes the 

 resident active members of the New York 

 Academy of Sciences, the Torrey Botanical 

 Club, the Linnaean Society of New York, the 

 New York Mineralogical Club, the American 

 Mathematical Society, the New York Section 

 of the American Chemical Society, and the 

 New York Entomological Society has nine 

 hundred and thirty-nine members. An act 

 of incorporation, formally accepted by all 

 the societies, has been obtained from the 

 Legislature of New York. Bulletins are issued 

 about the 1st of each month from October to 

 May, and announce most of the stated papers 

 read before the societies. The list of the 

 last year's papers includes upward of one 

 hundred and eighty titles. A building com- 

 mittee has been appointed, but is at present 

 awaiting the action of the trustees of the Til- 

 den Trust upon a proposition made to them 

 in 1892. Verbal assurances have been re- 

 ceived from individual trustees that their 

 plan of building contemplates giving the so- 

 cieties ample and very satisfactory accommo- 

 dations in the building of the New York Pub- 

 lic Library. 



A New Variable Star. The period of 

 Wells's new variable star of the Algol type, 

 known as B. D. + 17 436Y, has been ascer- 

 tained at Harvard College Observatory to 

 within a few seconds, and will probably be 

 known within one second as soon as the form 

 of light curve is determined. For nearly 

 two hours before and after the minimum it 

 is fainter than the twelfth magnitude. It 



increases at first very rapidly and then more 

 slowly, and attains its full brightness, mag- 

 nitude 9*5, about five hours after the mini- 

 mum. Its variations may be explained by 

 assuming that the star revolves around a 

 comparatively dark body, and is totally 

 eclipsed by it for two or three hours, the 

 light at minimum, if any, being that of the 

 dark body a condition resembling those of 

 U. Cephei. The variation in light of the 

 new star is greater than that of any other 

 star hitherto discovered. 



A New Library Pest. A comparatively 

 recent importation, which is described in 

 Insect Life, is the Nicobium (Anobium) hir- 

 tum III of the coleopterous family Ptini- 

 dce. It is a native of southern Europe, but 

 has been occasionally found in American 

 libraries for a number of years. It seems 

 now, however, to have become quite abun- 

 dant, and is doing considerable damage in 

 some of the older libraries of the Southern 

 States. The larva of Nicobium hirtum does 

 not differ in general appearance from other 

 ptinid larva? i. e., it closely resembles a 

 white grub in miniature, in shape and char- 

 acteristic curvature of the body. It is cov- 

 ered with sparse but rather long hairs, while 

 even a feeble magnifying glass will show 

 numerous short, brownish spines, with which 

 the larger portion of the dorsal surface is 

 furnished. Although the legs are well de- 

 veloped, the larvae are barely able to make 

 use of them, and if shaken from the books 

 they are unable to climb back to the shelves. 

 They attack especially old books with soft 

 paper and paper bindings. The beetle is of 

 elongate, oval, cylindrical form, 0'12 to 0'16 

 inch in length, its color rather light brown, 

 but rendered grayish by a dense, short, and 

 somewhat velvety pubescence. This pubes- 

 cence, however, does not uniformly cover 

 the elytra, but is here absent on two or three 

 transverse bands of which the anterior is 

 usually quite distinct, while the two posterior 

 ones are less clearly marked out and often 

 confluent or broken up into spots. This 

 peculiar arrangement of the pubescence, as 

 well as the strongly punctate elytral striae, 

 render this species at once distinguishable 

 from all other beetles which are liable to 

 occur in the rooms of a library. 



