180 



Observations on the Potatoe Disease. 



Vol. XI. 



practised it assured me, that no taste or 

 odor is preserved in the flour or bread pro- 

 ceeding from that wheat. 



" Some precautions ought to be observed 

 in using this process, in order that the la- 

 bourers should not be suffocated by the gas 

 emitted in the granary. The latter should 

 be well aired by two large openings situated 

 at opposite sides ; and the operation should 

 be performed when the wind blows hard 

 enough to create a strong draught. The 

 person who pours the grain in the cask 

 being the most liable to be incommoded by 

 the gas which is displaced, must always put 

 himself to the windward side of the cask, 



" For the use of large establishments an 

 apparatus might be easily contrived, by 

 means of which the operation could be per- 

 formed in a continuous manner, by intro- 

 ducing a stream of sulphurous gas in a ver- 

 tical tube made of four boards, through 

 which the grain would be sent from the 

 upper to the lower story; but for the use of 

 a farmer, or of any other person not having 

 a very large quantity of grain to be operated 

 upon, I think the use of casks will be the 

 most commodious application of this me- 

 thod. 



" I think it probable that the germinative 

 faculty shall not be affected in the grain by 

 the application of sulphurous gas; but it may 

 be interestiing to inquire whether this ap- 

 plication would not be more efficacious 

 against the propagation of smut, than the 

 other methods hitherto employed. If it be 

 indeed true, as is generally believed, that 

 the action of lime and of sulphate of copper 

 destroys the seminiform buds of smut, we 

 may anticipate the same and a more ener- 

 getic effect from acid sulphurous gas ; and 

 the application of this process would be cer- 

 tainly the easiest and the least expensive of 

 all those, that have been hitherto suggested 

 to answer the purpose." 



For the Farmers' Cabinet. 



Observations on the Potatoe Disease. 



Mr. Editor, — You are aware that many 

 persons believe that the potatoe disease is 

 caused by wet weather. This is more par- 

 ticularly the case in Europe. There, the 

 wet weather that has preceded and attended 

 the disease, has been, sq far, very constant 

 I have before me a paper giving the most 

 distressing accounts of the disease in Ire 

 land, in which it is stated that about the 

 commencement of August, there were a 

 few very foggy nights, and that during this 

 time the potatoes became attacked with the 

 disease, and in less than a week, the fields 



which at that season should present a vivid 

 green, looked as black and as withered as if 

 the month was October, not August. This 

 fact, with many others of a like nature, in- 

 duce them to think that the fog and wet 

 weather are causes of the disease. 



I have mentioned in one of my communi- 

 cations that heat and moisture are necessary 

 for decay. In the early part of the month 

 of August there is always sufficient heat for 

 decay, and the only remaining ingredient, 

 moisture, being furnished by the fog, we 

 should not at all be astonished at the rapid 

 progress of the disease, and that the fields 

 which had looked so beautiful, should so 

 soon change and put on the livery of death. 

 The decay of other vegetation, and other 

 causes generated carbonic acid, which killed 

 the potatoe tops ; these rotted and increased 

 the supply of carbonic acid. The potatoes 

 themselves absorbed the carbonic acid, and 

 they, too, began to rot; and unless the heat 

 and dampness were decreased, there would 

 hardly a potatoe be seen at the commence- 

 ment of October. 



Decomposition, however, may progress 

 without moisture, but in such cases it re- 

 quires more heat. Fire will decompose 

 wood and other vegetable matter, even when 

 very little moisture be present; in fact, the 

 less moisture there is present, the more ra- 

 pidly the decomposition progresses. This 

 decomposition generates carbonic acid, as 

 in the slower processes. But decomposition 

 will progress very fast with much less heat, 

 provided there be moisture present. The 

 hydrogen of the water seems to aid the de- 

 cay. Thus, when the water is sufficiently 

 abundant to supply the full quantity of hy- 

 drogen that' can be used by the decaying 

 vegetable, even if the heat be not very 

 great, the work of decay progresses very 

 rapidly, generating carbonic acid, and dis- 

 easing and destroying the potatoes. Hence 

 the reason is obvious why the potatoes de- 

 cayed so rapidly in Ireland at the time of 

 the fog. 



Had the potatoes been supplied with fresh 

 and strong alkaline substances, they would 

 have been enabled to absorb all the carbonic 

 acid, and appropriate it to the formation of 

 starch, and thus escaped death and decay. 

 But being starved out of this substance, 

 which enters largely into their formation, 

 they were weakly, and where they were 

 thus exposed, they could not do anything 

 else than yield to the powerful influence of 

 the disease. Thus the cause which should 

 have been the farmers' friend, and increased 

 his crop, has, in consequence of his want of 

 knowledge of its nature, been to him a 

 most dreadful and unsparing enemy. May 



