I. AGRICULTURE AND RURAL ECONOMY. 423 



so late that the stalk did not grow again, and under any 

 circumstances the yield seemed poorer in quality and quan- 

 tity than without topping. Although the stalks topped at 

 the proper time had fewer diseaseji tubers, the spores of the 

 fungus seem to be carried to the tubers through the stalks 

 rather than by rain, otherwise the topped stalks would have 

 received a supply from the neighboring ones. In warm, dry 

 weather the increase in growth is greater than in cool, wet 

 periods. Early kinds of potatoes seemed to do better than 

 late ones. Heavy manuring, especially with horse or sheep 

 manure, favored the disease, and increased the watery con- 

 tents, and the yield was also less, although with luxuriant 

 growth of the stalks. 28 (7, May, 1873, 403. 



UTILIZATION OF THE " CAT-TAIL." 



To the list of waste vegetable i^roducts that are now be- 

 coming utilized is to be added the common " cat-tail," a plant 

 that abounds in many marshy districts to a very great ex- 

 tent. M. Dupont prepares the fibre by boiling the cut and 

 dried leaves for several hours in an alkaline solution, and 

 then pressing between rollers, and washing. Thus prepared, 

 it is valued at from %1 to $8 per hundred weight ; and it is 

 estimated that France is capable of producing at least 100,000 

 tons yearly. The fibre is yellowish, but takes dyes readily. 

 It is quite tenacious, and can be worked up into cordage or 

 converted into paper. 18 A, May 16, 1873, 217. 



SPOXTAXEOUS COMEUSTIOX OF HAY. 



A scientific basis has generally been conceded to the opin- 

 ion that hay stored when not perfectly dry is liable to spon- 

 taneous ignition. The following communication by Ranke 

 fully substantiates the opinion, and throws light on some of 

 the conditions involved. Two stacks of second-crop hay, 

 containing respectively about twenty-two and fifteen tons, 

 in apparently perfectly dry condition, Avere formed in a barn, 

 between the 5th and 10th of August, during excellent weather. 

 The usual strong hay aroma was perceptible, increasing in 

 intensity until the 17th of October, when it was replaced by 

 an empyreumatic odor from the larger stack, which had a 

 length and height of twenty-three feet and a width of sixteen 

 feet. Althougl), externally, the color ami temperature were 



