OcTOBEB 29, 1886.] 



SCIENCE. 



387 



two thirds of steam, on leaving the high-pressure 

 cylinder, passes into another, is expanded at two- 

 thirds the stroke, and, having exerted its power, 

 proceeds to a pump, where it is again expanded. 

 After this the two-thirds steam is compressed in 

 the last pump into the one-third feed-water ; this 

 latter process is carried on at the expense of 

 engine-power, which is exerted not only in forcing 

 the steam into the feed-water, but in compressing 

 a cushion of air maintained at a proper pressure 

 by means of air-pumps. This cushion or air- 

 spring, on the return stroke, renders up its stored 

 energy by pushing or returning the combined 

 feed of steam and water back to the boiler. 



— The next meeting of the Indiana academy of 

 sciences will be held at Indianapolis, Dec. 29. It 

 is proposed that the papers presented to the acade- 

 my be grouped according to the topic ; that is, 

 that ail papers upon geology be brought together, 

 and all upon biology, etc. Those who desii'e to pre- 

 sent papers should, at their earliest convenience, 

 send the titles of their communications to the 

 secretary, Mr. Amos W. Butler, Brookville, Frank- 

 lin county, Ind. 



— The new U. 8. cruiser Boston. Mr. Gould's 

 yacht Atalanta, and Mr. Vanderbilt's yacht Alva, 

 are to be furnished with dense-air ice-macliines, 

 which are now being built at the Delamater iron- 

 works in this city. In these machines, which re- 

 quire no chemicals, the air is compressed and ex- 

 panded betv/een the limits of twelve and four 

 atmospheres' pressure, being used over and over 

 again in what is called a ' closed cycle.' In the 

 ordinary cold-air ice-machines the air is com- 

 pressed and expanded between the limits of the 

 normal atmospheric density and three or four 

 atmospheres. The lower limit of density in the 

 new machines — four atmospheres — is produced 

 and maintained by a small auxiliar}^ air-pump, 

 which is automatically thrown out of action when 

 the proper pressure is reached, resuming again 

 when, through leakage, the pressure is reduced. 

 It is said that with these machines ice may be 

 produced at a cost of two dollars per ton. 



— The electric motor is destined to play an im- 

 portant part in the history of railroads in this as 

 well as other countries. Although not yet out of 

 the experimental stage, electric street railways are 

 rapidly gaining ground in public favor. Chicago, 

 Baltimore, Philadelphia, Minneapolis, Toronto, 

 and other cities already have electric street-rail- 

 ways in successful and protitable operation. 

 About a dozen new roads are in course of con- 

 struction, and a score or two more are projected. 

 Montgomery, Ala., will be the first city in the 

 world to have a complete electric street-railway 



system. In this city it is expected that a new 

 and powerful Daft electric motor will soon be 

 making trial trips on the Ninth Avenue ele- 

 vated road, hauling a train of four or five cars ; 

 and on a branch of the Third Avenue road a pas- 

 senger-car equipped with Sprague motors has been 

 making experimental trips during a great part of 

 the summer. 



— The contributions to the mineral wealth of 

 the world from the mines of Victoria, Australia, 

 up to the beginning of the present year, show the 

 very respectable total value of $1,052,635,824, 

 This is divided as follows : gold, $1,047,129,274 ; 

 tin, $3,239,524 ; copper, $920,000 ; antimony, $824,- 

 466 : silver. $350,840 ; coal, $84,738 ; iron, $61,045; 

 lead, $25,937. During the past year there was a 

 total of 26,192 persons engaged in mining in Vic- 

 toria, of which number 4,950 were Chinese. It is 

 noticeable that of the latter there were only 202 

 engaged in quartz-mining, the rest working at the 

 alluvial or placer diggings. 



— The tincture of the chloride of iron, diluted 

 with water, is very generally used as a tonic. 

 Recent experiments have thow.-n that when thus 

 diluted it acts very injuriously upon the teeth. 

 This is explained by the fact that the peroxide 

 formed in the alcoholic solution is precipitated 

 when water is present in such a flocculent form 

 as not to adhere to the surface of the teeth, and 

 consequently the free hydrochloric acid can act 

 upon the lime salts of the teeth without let or hin- 

 derance. When the tincture is given without 

 water, no action takes place ; the peroxide which 

 is then formed i? of the anhydrous form, and so 

 compact as to adhere to the teeth, and protect 

 them from the action of the acid. These experi- 

 ments have resulted in determining that there 

 are three menstrua which can be u^ed as diluents 

 of this tincture, which will produce no injurious 

 effects upon the teeth : they are alcohol in some 

 form, vichy water, and a simple sirup. 



— Professor Legge states that he has foimd two 

 embryos in a single blastoderm Ln a fowl's egg at 

 the third day of incubation. 



— A remarkable death has recently occurred in 

 Paris, in which the cause would never have been 

 discovered had not an autopsy been held. A 

 young girl was found dead in the street, and was 

 at first supposed to have been the victim of foul 

 play. When the post-mortem examination was 

 held, the larynx was found to be closed by lum- 

 bricoid worms, which had been vomited, but had 

 not been ejected from the mouth. 



— The report of the director of the Leander Mc- 

 Cormick observatory of the University of Virginia, 



