76 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



that a cyclone is formed or not. These signals are displayed 

 at four stations on the coast. Report Meteor. Reporter for 

 Bengal for 1872; and Report 3Ieteor. Reporter for Bombay 

 for 1873. __ 



MOVEMENT OF STOKM-CENTRES. 



The laws of the movement of storms are now bem dili- 

 gently studied at all the national meteorological institutions 

 of the world, and at none are there better means of pursuing 

 such studies than at St. Petersburg and Washington. The 

 rules adopted by Professor Abbe were indicated in a popular 

 pamphlet published in the spring of 1871, soon after the 

 Army Signal-office began to issue the tri-daily weather prob- 

 abilities as compiled by him. In this pamphlet the connec- 

 tion between an abnormal rise of temperature and the proba- 

 ble future course of a storm-centre is dwelt upon; and w t o 

 have now to record a valuable investigation into the details 

 of this connection by Lieutenant Baron Maydell, assistant at 

 the Central Physical Observatory at St. Petersburg, who 

 states that his attention was specially called to this by the 

 study of the storm of February, 1873. From the considera- 

 tion of all the storms of Northern Europe during 1872 and 

 1873, Maydell deduces the following generalizations. 



In advance of such barometric minima as make themselves 

 felt on the west coast of Norway, the tension of the aqueous 

 vapor and the temperature, to a certain distance south of this 

 place, rises. In the progress of the storm-centre both these 

 elements, temperature and tension, retain, for any given day, 

 to a greater or less extent, the same position in reference to 

 the barometric minimum, and therefore must advance in the 

 same direction with it. The variations of absolute humidity 

 correspond closely to those of the temperature. 



In attempting to make use of the temperature changes in 

 his predictions of storms, Maydell concludes as follows : The 

 storm-path for the next twenty-four hours forms a determi- 

 nate angle with the line connecting the present place of the 

 barometric minimum with that of greatest rise of tempera- 

 ture. This angle is always formed on the left hand of that 

 connecting line, supposing the face to be turned toward the 

 point of rising temperature, and the back toward the point 

 of minimum barometer. This angle he finds to vary between 



