338 Wear and Tear of Agricultural Steam-Engines. 
accumulation of tlie straw about the premises at certain seasons 
i)i tlie year. 
It may be useful to know how much chaff, well trodden in, 
will <jo into a certain space : one of our own chaff-houses, in 
which we have tried the experiment, is 35 feet long, 15i feet 
wide, and 11 feet high. Its content is therefore 5967 cubic feet, 
and it holds 19^ tons of wheat-straw chaff, = 306 cubic feet per 
ton. Eight acres of mown wheat-straw, of last harvest, rather a 
heavy crop, weighed exactly 12 tons, and occupied a space, when 
trussed and stored in the straw-rick, of rather more than 12,000 
cubic feet. In round numbers, trussed wheat-straw occupies a 
space of 1000 cubic feet per ton : — more, if stored loose and un- 
trodden ; less, if well trodden with horses: cut into short chaff 
and well trodden, it takes less than one-third of that space. 
The combined arrangements for threshing and cutting chaff 
at the same time, are becoming all the more practicable from 
the increased power of the engines in common use. In 1851 
the average of the portable engines made by Messrs. Clayton 
and Shuttle worth was five-horse-power, and in 1855 nearly 
seven-horse-power. And as the question of steam-ploughing 
becomes more and more one of practical utility and economy, 
there is no doubt that the larger engines will be the most 
desirable upon farms. 
Gosfield, Hoisted. 
XX. — Tlie Present State of the Sewers and Water Su])])Ii/ of 
Paris. By P. H. Frere. 
England may well look with interest to the changes made or 
contemplated in France for the disposal of that town-refuse which 
is a possible source of wealth, but, if ill dealt with, a certain cause 
of annoyance ; and indirectly its Agriculture is concerned in the 
result. With us, to a certain extent, the die is cast ; the contents 
of the closet have penetrated, with the kitchen refuse, «Scc., into 
the common sewer, into which they are washed by an unre- 
stricted supply of water. To set up a wall of separation^ — to limit 
the amount of dilution — would in themselves be steps of extreme 
difficulty, because in one sense retiograde. Paris, on the other 
hand, is still, in the main, uncompromised. That city is in a 
state of transition ; generally the old-fashioned pit still exists, for 
the most part unsupplied with water ; but a large water-supply 
has been procured for houses of the better sort. But even then 
the soil-pit still remains wholly or partially separated from the 
common sewer, and the question still is to be decided whether 
