OF AKTS AND SCIENCES. 15 



been, from the beginning of this investigation, an essential in its con- 

 tinuance. Mr. H. Helm Clayton, now observer at the Blue Hill 

 Meteorological Observatory, has also given valued assistance in chart- 

 ing certain storms. But even with so much effective help, a long delay 

 in presenting this statement of our last summer's work has been un- 

 avoidable. The discouraging effects of the delay may, however, be 

 more than counterbalanced, if the report reaches our observers at the 

 opening of another thunder-storm season, and, by pointing out the 

 value of the work done last year, encourages them to still further 

 efforts in a second campaign. These efforts should be of two kinds. 

 First, the enlistment of new volunteers in neighboring towns ; it is 

 hoped that our observers will take care — will indeed take pride in 

 seeing that no large district remains unrepresented on our lists. 

 Second, in giving special attention to certain questions which are 

 mentioned in the following pages as needing well-directed, discriminate 

 observation for their deci:?ion ; among these, the growth and motions 

 of the storm-clouds, whether observed near at hand or on the distant 

 horizon, may be named as of the first importance. 



It is worth while to state here that one of the most serious difficuL 

 ties that we have had to contend with is the lack of belief in the im- 

 portance of trivial observations. Many observers have expressed some 

 misgivings as to the value of their work, because they had only light 

 rain and faint thunder to report ; and some persons seem really to have 

 been discouraged even to the point of giving up their records, because 

 they were not favored with any violent storms. It would take but a 

 short time to convince all these observers that very simple records in 

 many cases possess the especial interest of marking the beginning, end, 

 or border of violent storms, without which it would be impossible to 

 define the storm area or tract. Even the simple and direct statement 

 of iVo storm to-day is important, as, for example, on July 3, when many 

 small storms developed in eastern Massachusetts and moved out to sea. 

 By consulting the map for that day, it will be perceived how important 

 the report of " Distant thunder, but no rain," may become, when com- 

 bined with observations at other stations. It is therefore especially 

 desirable that observers should in all ca,ses follow instructions as closely 

 as possible, lohether their record seems important or not. The impor- 

 tance of an observation appears when it is brought together with all the 

 other records of the same day. It is probably for similar reasons that 

 many persons failed to see the necessity of timing their observations 

 accurately ; a record that gives time only in round numbers, such as 

 3.50, 4.10, 4.30, is at once open to suspicion ; while one in which un- 



