344 PROCEEDINGS OF THE AMERICAN ACADEMY 



five. Requested: time and amount of hail ; time and direction of heat- 

 liofhtninsr; notes on wind. 



Class B. — Required: time and direction of first and loudest thunder ; 

 temperature, wind (force and direction), and sky at time of first thunder, 

 and then every even half or quarter hour (e. g. 3.00, 3.30, 4.00, etc.) 

 as long as thunder is heard ; time, direction, and force of wind-squall, 

 and its temperature ; time of first, heaviest, and last rain, its estimated 

 amount, and temperature of air at its beginning and end. Requested: 

 notes on violence of rain at various times; frequent observations (even 

 every minute) of temperature during squall ; heat-lightning, lightning 

 strokes, and notes on clouds. 



Class C. — In addition to the requisitions in Class B, observations are 

 here desired on clouds ; first appearance and motions of cirro-stratus, 

 cumulus, squall-cloud, festoon-cloud ; appearance of distant storms ; 

 determination of growth or dissolution of clouds by watching changes 

 at their margins ; angular altitude and direction of same clouds from 

 time to time as storm approaches, giving basis for determination of 

 altitude when velocity is known ; sketches of clouds ; self-registering 

 instrument of some kind, and observations of humidity ; photographs 

 of clouds and lightning. 



It is not intended that Classes B and C should be rigidly divided ; 

 slight changes can be made at the observer's pleasure, but every one 

 must do at least the requirements of Class A. Change of station is also 

 permitted, as we thus gain more than we lose ; but permanent residence 

 through the summer is desirable. 



It is often nearly as important to know that a storm did not appear 

 at a certain station, as to have a record of it. It is therefore proposed 

 to ask all observers to keep a very simple journal, stating for every 

 day merely whether it was clear, fair, cloudy, rainy, or stormy, and 

 sending in this record at the end of every month. This will insure 

 continuous record, and will at the same time give data for the sharp 

 limitation of storm areas ; actual denial of storm being much safer for 

 this purpose than simple absence of report. 



I am well aware that the tasks here set are rather severe, but the 

 experience of last summer justifies the expectation that they will be 

 well borne. There is no question whatever that every post-office town 

 in New England contains residents fitted and ready to undertake the 

 records of Class A; the difficulty that we encounter is not in jier- 

 suading them to do the work, but in finding the right persons. An 

 essential in the scheme is therefore a much greater notoriety than 

 is needed in most scientific investigations ; for this we count largely 



