AMERICAN INSTITUTE. 259 



Lately entomologists have discovered another fruit enemy of pit-fmitx, 

 a very small insect, the Tipvla. The female puts an egg into the head of 

 pear, when it is as large as a hazel-nut. The worm, of /nicroscopic size, 

 opens a gallery to the centre of the fruit, and after iv^ards makes another 

 gallery leading out of the pear ; it falls, and the worm buries itself 

 in the earth, and afterwards becomes a butterfly, the ferfect insect. Raise 

 the soil around the trees, and Tipula is destroyed, for he is only two centi- 

 meters (seven-eighths of an inch) deep, and cannot escape when covered 

 deeper. YSABEAU. 



[From the London Times.] 



THE UPS AND DOWNS OF WHEAT. 



]\rr. C. Wren Hopkins writes to the Times: "For a period of no less 

 than thirty-two years, ever since 1827, the price of wheat has moved in 

 quadrennial periods. Four years up and four years down, with a regu- 

 larity so steady and invariable that it is difficult to cast one's eyes over the 

 scale of " annual averages" and escape the impression that it is a perfect 

 natural cycle. 



" No expression of words will do justice like the diagram of annual pri- 

 ces. It is as follows :" 

 From 1827 to 18."1, price rose from 58s. to 66s. 



1831 to 1835, price fell from 66s. to 58s., 52s., 46s., and 39s. 



1835 to 1839, price rose from 48s. to 55s., 64s., 70s. 



1839 to 1843, price fell from 66s. to 64s., 57s., 50s. 



1843 to 1847, price rose from 50s. to 51s., 54s., 693. 



1847 to 1851, price fell from 50s. to 44s., 40s , 38s. 



1851 to 1855, price rose from 41s. to 53s., 72s., 74s. 



1855 to 1859, price fell from 69s. to 56s., to the lower rate. 



In the retrospect of the prices long ago, we find these ebbs and flows of 

 prices recorded, but not so exactly in quadrennial periods. — H. Meigs. 



A NEW MOWING MACHINE. 



Chester Bullock of Jamestown, New York., exhibited a model of a new 

 plan of mowing machine. The blades work from the point in such a man- 

 ner as to give a more perfect, shear-cutting motion. The idea is that it 

 will work with less power, and will not clog in any kind of grass. 



AN IMPROVED REAPING MACHINE 



Which is claimed to be an improvement upon Jerome's machine, was 

 exhibited. One of the principal improvements is, the raker sits upon a 

 seat and rakes the grain off", so as to be out of the way of the next round. 



Prof. Nash explained that the principle upon which nearly all mowing 

 machines cut, is that of shears, whether the knives move on a bar or swing 

 from a pivot at the point or heel. He thought there must be a positive 

 advantage in the principle of Mr. Bullock's machines. The motion gives 

 a greater drawing out. 



