February 15, 1889.] 



SCIENCE. 



117 



condensed vapor to be covered by coal-smoke. These fogs usually 

 accompany a high barometer, and are frequently dry in their char- 

 acter. 



It is a well-known fact that cold air on the tops of hills, being 

 heavier than the air below, slides down the slopes ; so that the 

 lower parts of hillsides are actually colder than the plains at some 

 distance from the hills. Now, London, in the Thames valley, is 

 surrounded by hills, — to the north, Highgate, Hampstead, and Har- 

 row ; in a westerly direction. Putney and Wimbleton ; and in a 

 more southerly direction, Clapham and Sydenham. The air is 

 colder on these hills than in London, with its, millions of inhabit- 

 ants, its coal-fires and factories : hence it is heavier, and will 

 have a great tendency to slide down the hills towards the town and 

 the river. Should the air in town be on the point of saturation, 

 and the cold air from above saturated with vapor, it is obvious that 

 the increased cold from above will produce a precipitation of moist- 



working drawings made, but actual construction is required, and is 

 made possible in extensive workshops, the equipment of which has 

 cost over forty thousand dollars. In electricity, in addition to the 

 instruments and appliances usually found in electrical laboratories, it 

 possesses the most complete and accurately adjusted series of Sir 

 William Thomson's electrical balances in this country ; and there 

 is a completely equipped testing-room for the purpose of calibrat- 

 ing and standardizing commercial instruments. Another impor- 

 tant feature is the restriction placed upon the number of students 

 admitted. The plan of the institute is to limit the attendance to 

 such an extent as to realize the great benefits arising from small 

 classes. Ample facilities will therefore be afforded to all who 

 undertake its courses of study. Those who are contemplating 

 preparation for either mechanical, civil, or electrical engineering, 

 will do well to consult the catalogue of the Rose Polytechnic Insti- 

 tute. 



^AGUE ELECTRIC ROAD AT READING, PENN 



ure, and it will come to pass that a fog is produced. If the hill- 

 tops be not only colder than the air below, but enveloped in a fog. 

 it stands to reason that the fog below will be all the denser, and 

 especially in the neighborhood of water, such as the river Thames, 

 and the ornamental waters in the parks. 



. THE ROSE POLYTECHNIC INSTITUTE. 



The Rose Polytechnic Institute is one of three or four 

 schools in the United States which are especially devoted to the 

 education of civil, mechanical, and electrical engineers. It owes 

 its existence to the generosity of the late Chauncey Rose of Terre 

 Haute, Ind., who bequeathed something more than half a million 

 of dollars for its establishment and support. It is one of the 

 youngest of the technological schools of the country, having been 

 opened in the year 18S3. One of the peculiar features of the insti- 

 tute is the thorough and extensive " shop-practice " of the students 

 in mechanical engineering. Not only are machines designed, and 



THE DERELICT AMERICAN SCHOONER 

 WHITE." 



W. L. 



Mr. Everett Hayden, meteorologist to the Hydrographic Of- 

 fice, has compiled the reports on the history of the derelict schooner 

 " W. L. White," and the results of his investigation have been pub- 

 lished on a supplement to the monthly " Pilot Chart," a portion of 

 which is reproduced here. Besides showing the track of the " W. 

 L. White," those of the derelict barks " Telemach " and " Vinocuzo 

 Perrotta " have been plotted on the map. 



Mr. Hayden reports that a telegram dated Stornoway, Hebrides 

 Islands, Scotland, Jan. 23, iSSg, marks the termination of the re- 

 markable cruise of this derelict vessel. Abandoned off Delaware 

 Bay during the great blizzard, March 13. 18SS, she has now com- 

 pleted her long and erratic transatlantic voyage, and lies stranded 

 upon Haskeir Island, one of the inany little rocky islands of the 

 Hebrides, in latitude 57° 42' north, longitude 7° 42' west. The 

 track of this vessel, as plotted on the " Pilot Chart " from month to 

 month during this long interval, has been of constantly increasing 



