384 



J)r, Holyoke^s Meteorological Observations, 



taining tlie different means of S6 and 33 years, to take them for 

 the numbers of those years respectively, and not {qv four or jive 



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equal series. 



In the column of Greatest Chansre within S4? hours it should 



1)6 observed, that the day of the mouth, set down, raarlcs the ter- 

 mination of the change ; and the letters e^ n^ s^ tp used in this 

 column^ in parentheses, from the year 1804 to IS 1 3 inclusive, 

 denote respectively the times of the observations of ihe day^ viz, 

 8 A. M. Noon, Bunset, and 10 P. M. which limit that change. 

 It is not, however, to be understood, that a change of temj>erat»ire 

 from heat to cold, or the contrary, is hereby always indicated j 

 for the thermometer may continue to rise or fall after such obser- 



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ration ; for instance, the thermometer lowered from noon of the 

 18th to 8 A.. M. of the ^Oth of Jaly 1^01 ; but the numher of 

 degrees, wnicli it rises or falls, in a period not exceeding 54* hours, 

 only is indicated. When the period, elapsed between the obser- 

 vations, is just 24 hours, only one letter is used, viz. that, which 

 shews the time of the terminating observation. When two letters 

 are used, the former of them points out the time, when the period 

 of change commences, and the latter, when it terminates : thus, 

 in the year I'^Ol', in the column of Greatest Change within 24? 



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hours, we find March 3th SB"" (tn), hv which is to be undersitood. 



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that the greatest variation of temperature within any 21- hours, in 

 the month of March of that year, is to be reckoned from lO P. 

 M. of the 4th day to the Noon of the 6th day of the same, and is 

 S6°. When the greatest change is reckoned from one day to 

 iBLnother, it not unfrequeutly happens, that the lowest temperature 

 of the atmosphere is not expressed, and cannot be expressed, at 

 the times of the observations in the registers ; and of course, that 

 the greatest change iw reaZjf?^ cannot hereby be ascertained : thus 



the greatest change within Z^ hours, Feb. 10; 1810, reckoning the 



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