April 30, 1874J 



NATURE 



505 



each minimum and maximum epochal year, and one 

 year on each side of it, as is done by Mr. Meldrum, and 

 deducing a mean from each of three tri-yearly periods, 



^1 



ri 





'? 5 



•5? § to 



the agreement is close between the solar periods nnd 

 those of fluctuation in the lakes. 



The remaining observations are those of the U.S. Lake 

 Survey, and include only one period each of maximunr 

 and minimum in solar spots. The measurements of the 

 U.S. Survey arc reckoned downwards {xoxa a mark repre- 

 senting the high vvfater of 1838 in each of the lakes, but 

 in the table here given they have been reduced so as to 

 read upwards from an arbitrary line chosen 4 feet below 

 that datum. They are thus rendered more intelligible 

 and made to agree in sense with Prof. Kingston's 

 measurements. 



The result is the same in each of the lakes, only differ- 

 ing in amount by a few inches. A mean deduced from 

 the U.S. Lake Survey observations in Lakes Superior, 

 Michigan, Eric, and Ontario, gives a difference between 

 the years surrounding the maximum of i860 and the 

 minimum of 1867 of I4"64 inches in favour of the 

 former. 



2. Didi^iiim of Curves. — The curve representing the 

 fluctuation of Lake Eric from 178S to 1857 inclusive is 

 constructed on a careful discussion of the evidence col- 

 lected by Col. Whittlesey and given by him most fully in 

 the " Smithsonian Contributions to Knowledge '' for 

 i860. 



From 1788 to 1814 there are no accurate measurements 

 to any well-recognised datum line, and I therefore give 

 below the measurements and approximations on which 

 the general curve for these years has been constructed. 

 The description of the fluctuation of the lake will be seen 



in many cases to apply with verbal accuracy to the sun^ 

 spot curve. 



"1788 — 1790. By tradition derived from the early 

 settlers very high ; according to some as high as 1838, 

 but this is doubtful. 



" 1796. By the first emigrants and surveyors reported 

 as very low— 5 feet below 1838. 



" 1797. Rising rapidly. 



" 1798. Water continues to rise, but 3 feet below June 

 1838. 



" 1800. Very high ; old roads flooded. 



" 1801. Still high. 



" 1802. Very low ; reported by old settlers as lower than 

 1797. 



" 1806. Very low ; reported by old settlers as lower than 

 1801 — 2, and declining regularly to 1809 — 10 when it 

 reached a level by many considered as low as that of 

 1819. 



" 1811. Rise of 6 inches in the spring over 1810, by 

 measurement, and a fall of 2 inches. 



" 1812. Rise of 14 inches in spring over 18 10, by mea- 

 surement, and a fall of 3 inches. 



" 1813. Rise of 2 feet 2 inches in spring over 1810 by 

 measurement. 



" 1814, Rise of 2 feet 6 inches in spring above general 

 level of 1 81 3." 



From 1815 to 1833, both inclusive, occasional measure- 

 ment to fixed data exist ; the supplementary notes are here 

 given. 



" 1815. Rise of 3 feet above average level of 1814. (This 

 statement is not confirmed by an actual measurement 

 made in August, and is probably exaggerated). 



" 1 8 16. Water still high, but falling, and continued to 

 fall till 1 8 19. 



" 1 8 19. Lowest well-ascertained level of the waters in 

 Lake Erie. 



" 1820. Stated to be in August as low as 1819. 



" 1 82 1. Rising. 



" 1822. Rising ; in the spring 4 feet below June 1838. 



" 1823. Rising ; in the spring 3 feet 3 inches below 1838. 



" 1824. Rising gradually. 



" 1825. Rising ; lowest level 3 feet below June 1838. 



" 1826. Rising ; lowest level 2 feet lo inches below June 

 1838. 



" 1827. About the general level of 18 15. 



" 1829. Water still rising. 



" 1830. General level same as 1828. 



" 1831. Lower than last year ; yearly change at least 

 3 feet. — Col. Whiting. (Probably an error as this would 

 place the water unprecedentedly low. Co). W'hiting pro- 

 bably ascertained that the lake was falling and erred in 

 taking some former high-water mark for that of the pre- 

 ceding year). 



" 1832. General average 2 feet 10 inches below June 

 1838. 



"1833. General average 3 feet 2 inches below June 

 1838." 



From this date to 1857 many actual measurements are 

 given by Whittlesey, and from these the curve for those 

 years has been constructed. The whole of the observa- 

 tions are reduced as nearly as possil:)le to the average 

 level for each year by comparison with a mean annual 

 curve for about 10 years constructed from monthly 

 averages of bi- five-day means gi\'en by the U.S. Lake 

 Survey. 1859 to 1869 both inclusive are from yearly 

 means derived from continuous observations at Cleveland 

 by the U.S. Survey. 1S71 to 1873 are from information 

 kindly furnished by Gen. Comstock, Director of the Lake 

 Survey. I have no data for 1870. 



The earlier and less systematic observers of the fluctua- 

 tions of the lakes would scarcely give attention to any but 

 the more important chanijes of level, and it is possible 

 that these in man\' cases may have been e.vaggeratcd in 

 amount. It would seem improbable, however, from tlie 



