646 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



invited criticism, for he had only made a small model, which works well, 

 but there may be some serious objection to its operation on a large scale. 



Mr. S. H. Maynard expressed a doubt as to the ability to throw this bridge 

 across a stream having- a strong current. All the pontQons he had seen 

 required to be anchored. 



Mr. Bartlett thought it would not be necessary to anchor more than one 

 in five of the floats. If they were made in cylindrical form, as proposed, 

 there would be danger of rolling. The contrivance appeared to be worthy 

 a trial. 



The Weather. 



The Chairman introduced to the audience Mr. D. Dick, the inventor of the 

 well known anti-friction press, who entertained them for a half hour with 

 his views regarding the periods of return of similar weather. He had been 

 a careful observer since the year 1813; that season the crops failed, and 

 the timothy run out from the excessive moisture and wild grass took its 

 place. He was then a young lad. The disaster made a strong impression 

 upon him, and he determined to make accurate observations, to ascertain 

 whether there was a regular return of the extremes of heat and cold, of 

 dryness and moisture. After long investigation he had proposed a theory, 

 founded on the evolutions of the moon, comprised within the cycle of the 

 nodes, or a period of 18 years and 228 days. In illustration of this theory, 

 lie compared the dry weather of the latter half of August and the first half 

 of September, 1825, with the month of April, 1844, commencing on the 

 second day. A period of 3 cycles, equal to 55 years and 10| months, was 

 then presented; the very cold weather of 1719-80, was compared with the 

 cold weather of 1835-6 — the winter of the great fire in the city of New York. 



He next compared the very mild winter of 1827-8, with the summer of 

 1846 — one cycle — the heat and moisture of which summer caused many 

 apple trees to blossom three times, the same tree having on it fruit of three 

 different ages. The next illustration embraced three cycles from the warm 

 summer of 1798 to that of 1854. He closed with the prediction that the 

 winter of 1864-5, will be severe, but the months of March, April and May, 

 will be warm and moist; consequently there will be an early spring. The 

 winter of 1865-6, will be severe with much snow, and especially a very 

 deep snow about the first of March, 1866, being the return of the snow 

 storm of 18th to 21st of February, 1717, old style. It should be under- 

 stood that when protracted warm weather or drought occurs, its returning- 

 cycle may be in the winter, which will be intensely cold, without much 

 snow; but should the summer be warm and moist, the corresponding 

 weather of the succeeding cycle will be warm and moist, even if occurring 

 in the winter. 



Mr. T. C. Smith directed attention to the fact that our seasons were 

 becoming later. Mr. W. Sewell said he well remembered the winter of 

 1835-6 ; the temperature was 30" below zero. Mr. Stetson inquired 

 whether the observations detailed by Mr. Dick applied to any large 

 portion of the globe; that is, whether the same kind of weather would pre- 

 vail at the extreme north and south. Mr. Dick replied that the weather 

 might be excessively wet at the south and dry at the north, but whatever 



