Safety Rejected. 
[August, 
478 
the coke or anthracite fire used by Mr. Gibbs, and with the 
machinery for working the hay about in the stream of hot 
air (see “ Journal of Science for 1881, pp. 572, 573). By so 
doing he effects an apparent economy. But what does he 
substitute ? We cannot obtain power in any shape for 
nothing. To dry a wet material we must do one of two 
things : we must either expose it to an increased temperature 
or to a current of dry air. In a fine season we get one, 
sometimes both, of these agents for nothing, and need merely 
expose the material in thin layers to the sun and wind, as in 
common hay-making. Mr. Neison, instead either of sun- 
heat or furnace-heat, makes use of a source which persons 
who, like the majority of farmers, are unacquainted with 
physical science may possibly consider as cheap as the aCtion 
of the sun and wind. He builds up his stacks, as we under- 
stand, with grass containing its natural moisture, and per- 
haps soaked in addition with rain. Fermentation sets in, 
heat is generated, and, as is generally known, without some 
special arrangement the stack would take fire, as often hap- 
pens. But to prevent this danger Mr. Neison arranges pipes 
or channels in the stack through which the heated air is to 
escape, carrying off the moisture with it, and thus ultimately 
and in some fashion drying the hay. 
In how far this device is novel we cannot pretend to decide. 
It is not, we understand, protected by letters patent, and 
some of its advocates have had the questionable taste to 
sneer at Mr. Gibbs for having taken out patents for his in- 
ventions. But, unless our memory completely deceives us, 
we remember some forty years ago seeing it suggested in an 
old book, that, when hay has to be stacked in an imperfectly 
dry condition, a long sack should be first stuffed full of hay 
or straw, and set upright. Around this sack the stack was 
to be built. When it had reached its full height the sack 
was to be drawn out, thus leaving a chimney through which 
the heated air and vapours might escape. 
Again, Mr. J. W. Thomas, F.C.S., published in 1878 a 
work entitled “ A Treatise on Coal, Mine-gases, and Venti- 
lation,” in which arrangements for keeping down the tem- 
perature of hay- and corn-stacks by means of pipes are 
described and figured. 
However, the question is not so much the novelty and 
originality of Mr. Neison’s device as its efficiency. No one 
doubts that if we piie up a large heap of vegetable matter 
in a wet state fermentation sets in, and a very considerable 
heat is generated. Such instances as hot-beds, the “firing” 
of ground dye-woods if too damp, the spontaneous ignition 
