METEOROLOGY. 



447 



775 C. He finds the melting heat of white 

 ii l.l.i'i ('..mid that of gray cast iron 

 Mild stool molts at 1,475 C., serai- 

 iniltl at 1.455 C.. and hard steel at 1,410 C. 

 Th<- furnace for hard porcelain at the end of 

 the baking has a heat of 1,870 C. The heat 

 of a normal incandescent lamp is 1,800 C., but 

 it may U- pushed to beyond 2,100 C. Previous 

 determinations have been falsified by using for 

 ci'mparison the melting points of palladium and 

 platinum. Thus the temperature of the Besse- 

 mer process was fixed bv Langley at 2,000 C., 

 '-i! platinum seemed to melt rapidly in the 

 (lame. It does not really melt, but it merely 

 dissolves in the minute drops of melted steel 

 carried along by the gaseous current. 



rding to Caifietet, glass and porcelain 

 tiilies can ho soldered on to metals by furnishing 

 first the end of the glass tube which is to be 

 joined with a very thin deposit of platinum, and 

 then liy electrolysis with a copper ring. The 

 glass tn ho can thus be handled as if it were a 

 metal lube, and can be soldered by means of tin 

 on to iron, copper, bronze, platinum, etc. 



A now paint for preserving metals from rust 

 consists chiefly of a silicate of iron which is 

 found in the neighborhood of natural deposits 

 of iron ores, and which also occurs in veins in 

 deposits of granite that have become decomposed 

 l>\ contact with the air. It is mixed in a finely 

 divided state with oxidized linseed oil and var- 

 nish to form a paste. When required as a paint 

 it is thinned down with good linseed oil, to 

 which may be added, if wanted, a drier, such as 

 litharge, and whatever colors may be desired. 

 When applied to sheet iron the coating of this 

 paint was unaffected by warm water or steam, 

 acid and alkaline liquids, ammonia gas, hydro- 

 chloric-acid gas, and sulphureted-hydrogen gas. 



.M KTEOROLOGY. An account of the earli- 

 est meteorological observations and instruments 

 has lion published recently by Dr. G. Hellmann. 

 He divides the history of observations into three 

 periods : The first period ends in the middle of the 

 fifteenth century, and represents an epoch when 

 observations were only partial and without precise 

 objects. In the second period, of about two hun- 

 dred years, observations were made at least once 

 a day. The third period, in which observations 

 have been made systematically and with instru- 

 ments, dates from about the middle of the seven- 

 teenth century. It is not known who was the 

 first person that kept a regular meteorological 

 journal. Humboldt thinks it was Columbus, on 

 his first American vovage. The Italians, how- 

 ever, seem to have made daily observations from 

 the middle of the fifteenth century. The weath- 

 ercock is by far the most ancient meteorological 

 instrument. Exact attention was given to the 

 direction of the wind in the time of Homer and 

 Hesiod, eight hundred or nine hundred years 

 before Christ. The first special provision for 

 such observations was given in the Temple of 

 the Winds, at Athens, which was built about 

 one hundred years before Christ. In Charle- 

 magne's time. Eginhard described the winds by 

 the four points of the compass, and noted their 

 variations. The first instrument for measuring 

 the force of the wind is attributed to Robert 

 Hooke, 1607, and is the same as the one used 

 now as Wild's pendulum anemometer. The ab- 



sorption or organic hygrometer was invented 

 about the middle of the fifteenth century by N. 

 do Cusa, but it is usually credited to Leonardo 

 da Vinci. The first condensation hygrometer 

 was the device of Grand Duke Ferdinand II, of 

 Tuscany. The first continuous hygrometric ob- 

 servations were made bv II. Boyle, at Oxford, in 

 June, 1666. The first thermometer is attributed 

 to Galileo, toward the end of the sixteenth cen- 

 tury. The instrument was improved some years 

 later, when the graduation was marked by rid/res 

 in the glass, every tenth ridge boing enameled. 

 The first pluviometer was employed by B. Caselli, 

 in 1639, but a later date is generally assigned to 

 him. The discovery of the Torricellian tube in 

 1643 is too well known to need more than a men- 

 tion. Many other points are discussed by II err 

 Hellmann in his interesting work. 



The principal results of the deliberations of 

 the International Meteorological Congress, which 

 met at Munich in August, 1891, are summarized 

 as follow: All temperatures published after 1901 

 are to be referred to the readings of the air ther- 

 mometer. Actinometrical observations are not 

 held to be sufficiently certain to justify their gen- 

 eral introduction. The application of a venti- 

 lating arrangement to wet-bulb thermometers 

 was recommended. It was decided to count as 

 days of rain those on which O'OOS inch (or (M 

 millimetre) of rain was measured, and to print 

 monthly the days on which 0'05 inch (or 1 mil- 

 limetre) fell. A note is to be made in monthly 

 schedules cf the number of days in which about 

 half the country surrounding the station is un- 

 der snow. A new classification of clouds, pro- 

 posed by Dr. Hildebrandsson and the Hon. Ralph 

 Abercromby, was adopted by a large majority, 

 England and the United States voting against 

 it. A committee was appointed to consider the 

 general question of typical cloud pictures, tak- 

 ing this classification more or less as a basis of 

 arrangement. A report was adopted on the ob- 

 servation of the motion, etc., of cirrus and other 

 high-level clouds. It was decided that no in- 

 strumental results of wind observation should 

 be published, unless the instrument had been 

 previously compared, directly or indirectly, with 

 a standard. A proposal to recommend the adop- 

 tion of universal or zone time was rejected, on 

 the ground that climatological time alone can 

 be used for climatologieal inquiry; and it was 

 decided to insist in all publications on beginning 

 the day with midnight as hour. The confer- 

 ence determined to introduce the practice of cor- 

 recting barometrical readings for the force of 

 gravity at latitude 45 after the beginning of 

 the year 1901. An international meteorological 

 committee was constituted to prepare for a pos- 

 sible congress in Paris in 1896. Questions re- 

 lating to terrestrial magnetism were referred to 

 a special committee. 



Temperature. It appears from Mr. A. L. 

 Rotch's observations of temperature and atmos- 

 pheric pressure at Blue Hill Observatory, Mas- 

 sachusetts, that the wind velocity is two thirds 

 greater there than at Boston, about 500 feet 

 lower, but the difference changes for various 

 hours of the day. At low levels the wind force 

 generally increases from the early morning until 

 the afternoon, but the conditions are reversed at 

 higher levels. This fact was pointed out by 



