St ATE HORTICULTURAL SOCIETV. 39 



attention, and excited thought by presenting itself as a great problem 

 demanding solution, and as claiming the undivided intellectual resources 

 of the age to accomplish it. 



\\ henever this is the case, the teacher is welcome, and he has an 

 easy task, because his lessons will be appreciated and readily understood. 

 To a great extent the ojjerations and observations of the Signal Service 

 Corps have prejjared the pul)lic mind for effective instruction in Meteor- 

 ology by awakening, in many minds, an intense interest on the subject 

 of toretelling the weather. It has done more than this; it has done an 

 inestimable service to humanity and civilization by demonstrating that 

 the facts of Meteorology are capable of bemg systematically arranged 

 and constructed into a science. 



Like all branches of natural science, the foundation of Meteorology 

 must l)e laid broad and dtc\) in i>hysical facts, recjuiring for their accu- 

 mulation, long, patient, and exhaustive observation. When a sufficient 

 number of facts have been collected, they must be classified for study, 

 and collated to ascertain their whole meaning, and to discover the gen- 

 eral and special laws in which they have their origin and by which they 

 are governed. 



Meteorology is that extensive science which takes cognizance of- all 

 atmospheric changes, and explains their causes and laws. It conse- 

 quently embraces not only the variation in pressure, in temperature, and 

 in moisture of the air, but includes the phenomena of fogs, clouds, dew, 

 rain, hail, snow, winds, water-spouts, lightning, thunder, auroras, and the 

 electric and magnetic tension of the Earth and its atmosphere. It 

 therefore offers a wide field for investigation, and presents problems that 

 tax for their solution the utmost capacity of the mightiest intellect. 



We ha\e no design, even if we had the ability, to discuss the whole 

 scope embraced by this comprehensive science. Time and the occasion 

 demand that we confine ourselves to the humble task of merely stating 

 and explaining the general principles of the science and the causes of 

 its phenomena as far as they originate in, and are connected with our 

 Earth and its atmosphere. 



First ; there is the phenomenon of clouds, and consequently of the 

 stores of rain, hail, and snow they bear. What are the facts? A tropi- 

 cal rainstorm appears upon our Gulf coast, and traverses the Atlantic 

 front of the continent from the Rio Grande to the Gulf of St. Lawrence, 

 a distance of over 3000 miles, and then it passes on the ocean beyond 

 our observation. In its progress it deposits water from three to four 

 inches in depth throughout its entire course. As such a storm usually 

 passes any given point in a few hours, it cannot have any great width. 

 Suppose it to be even one hundred miles wide. Then if it held all the 

 water it discharged while under our observation, the water so held must 

 have been from seven to ten feet deep over its whole width. This we 

 know is an impossibility. 



Moreover, it came to us laden, and when it took its departure be- 

 yond our observation, it was unimpaired in energy and capacity. It is 



