LABORS OF THE JOINT COMMITTEE. 109 



motion of the air is produced and kept up by the volcano, 

 the result of which must be a condensation of vapor, un- 

 less the dew point is very low. So powerful is this ten- 

 dency, that in South America a dry season is sometimes 

 changed into a rainy one, by the bursting out of a volcano. 

 From these brief hints, we trust it will be acknowledged 

 that something has been gained explanatory of the pheno- 

 mena in question. But we must not stop here ; it is not 

 enough to know where it is raining at a given time, we 

 must know when it will rain where we are. For this pur- 

 pose it is of primary importance to know the direction in 

 which storms move, and also their velocity in all the differ- 

 ent seasons of the year. 



We would suggest, as the most effectual, and perhaps the 

 only, means of obtaining this end, an appropriation by gov- 

 ernment for the purchase of meteorological instruments, to 

 be presented to those academies, schools, and colleges, that 

 would pledge themselves to keep a journal of the weather, 

 according to a prescribed plan, for five years ; and send a 

 monthly statement to a meteorologist, to be appointed by 

 the government. If instruments were thus furnished for 

 one hundred observers, it is altogether probable two hun- 

 dred more would volunteer their services, knowing that their 

 labors would be one hundred fold more valuable in combi- 

 nation Avith others than they had hitherto been. 



With three hundred observers, properly located, no storm 

 could spring up within, or enter the United States, without 

 being constantly under the eye of at least two observers. 

 And thus its extent, its progress, and the direction of the 

 wind in its borders, would be fully known. Until this shall 

 have been effected by government, we entreat every gentle- 

 man to whom the report is sent, to consider it a patriotic 

 duty to furnish the means of enabling at least one faithful 

 observer of the weather, to transmit a series of observations 

 monthly, to William'.Hamilton, Esq., Actuary of the Frank- 

 lin Institute, Philadelphia. 



