152 SC1ESCE IX HHORT CHAPTEl^. 



movements on the revolving paper, and thus tells the his- 

 tory of the rainfall. The line is zigzag while the rain is 

 falling, and horizontal while the weather is fair. The 

 amount of inclination of the zigzag line measures the depth 

 of rain by means of the same ruled lines on the paper as 

 measure the height of the barometer, ete. Every time the 

 measuring vessel tips over a perpendicular line is drawn, 

 and the pencil resumes its starting level. The papers con- 

 taining these autographs of the elements may, of course, 

 be kept as permanent records for reference whenever needed, 

 or the results may be tabitlated in other forms. 



There are many modifications in the details of these self- 

 registering instruments. In some of them photography is 

 made to do a part of the work. The above description in- 

 dicates the main principles of their construction, without 

 attempting to enter upon minute details. 



Meteorological observatories are provided with these in- 

 struments, and all nations worthy of the name of civilized 

 co-operate with more or less efficiency in providing and en- 

 dowing such establishments. They are placed in suitable 

 localities, and communicate. with each other, and with cer- 

 tain head-quarters, by means of the electric telegraph. One 

 of these head-quarters is the Meteorological Office, at Xo. 

 116 Victoria Street, Westminster, S.W., which daily re- 

 ceives the results of the observations taken at about fifty 

 stations on the British Islands and the Continent. The 

 chief observations are made simultaneously at 8 A.M. 

 and telegraphed in cypher to London, where they usually 

 arrive before 10 A.M. As they come in they are marked 

 down in their proper places upon a large chart, and when 

 this chart is sufficiently completed, a condensed or abstract 

 copy is made containing as much information as may be 

 included in the small newspaper charts. This is copied 

 mechanically on a reduced scale on a slab on which t he- 

 outline chart has been already engraved. This engraving- 

 completed, casts are made in fusible metal with the black 

 lines in relief, for printing with ordinary type, and the 

 casts are set up with the ordinary newspaper types, and 

 printed with the letterpress matter. 



The engravings overleaf are taken from two of the news- 



