80 
Utilisation of Toim Seicage. 
is calculated to be 6"6G grains per jr-'^llon. Takinc: 10 lbs. of 
ammonia to represent the mixed excrements of one individual of 
a mixed population of both sexes and all ages for a vear, 1000 
tons of the sewage of either London or Rugby would, according 
to the above estimates, contain the excrements of about 21 or 
22 individuals. 
" V. Composition of the Unsewaged and Seivaged Grass. 
" It was obviously of great importance to determine the pro- 
portion of dry or solid substance contained in the produce cut, 
weighed, and given to the animals, in a green and verv succulent 
condition ; to determine the difference in composition due to the 
application of sewage ; and also that of the successive crops 
taken at different periods of the season. To this end samples of 
2i lbs. of the unsewaged, or 5 lbs. of the sewaged grass, were 
taken from every load as soon as it ^vas weighed at the home- 
stead, the samples from each plot respectively being mixed 
together day by day as taken, until the cutting of the plot was 
completed. Each such mixed sample Avas exposed on sheets of 
canvas in the open air until sufficiently dry. It was then stored 
in sacks, and finally cut into coarse chaff, well mixed, weighed, 
and a weighed portion of the mixture taken for the purposes of 
analysis. 
* " 50 ounces of the coarsely-cut chaff were taken in each case, and each of 
these samples was carefully divided into 4 equal parts ; two of which were fully 
dried at 212" F. to determine the absolute dry substance, and then burnt to deter- 
mine the mineral matter, and a third was finely ground, and a portion of it sent 
to Professor Way for analysis. 
" It should here be remarked that there are many practical difficulties in the way 
of getting accurate results in regard to the amount of dry substance in large balks 
of green produce such as those in question. Cut in the morning, as the crops always 
were, the grass generally held a good deal of superficial as well as other moisture, 
and, with equal conditions of weather, the heavier the crop the greater the amount 
of water so retained. Again, if the weather were dry and hot, the grass would lose 
moisture considerably between the time of cutting and that of weighing and saispling 
at the farm buildings ; or, if rainy, the grass would be more or less saturated with 
water. To add to these difficulties, which are almost inseparable from such aa 
inquiry, the taking of the samples, and their partial drying and preservation, were 
necessarily left in the hands of those unpractised in such work. 
" It will be obvious from the above considerations, that the exact figures given 
which relate to or involve the question of the proportion of dry substance in the 
produce must be accepted with some reservation ; though it is believed that at any 
rate the direction and more general indications of the results on the point may fully 
be relied upon. The results given of the analyses of the dry substance itself will, 
of course, be much less afi'ected by the irregularities referred to ; and the differences 
in its composition according to the difference in the conditions of growth are points 
well wortliy of a careful consideration in a hitherto untrodden field of inquiry. 
" It should be added that, taking advantage of the experience of the past year, 
all possible precautions are being taken to eliminate avoidable irregularities in the 
conduct of this part of the work during the present season (18C2) ; and to secure 
greater uniformity and certainty in the partial drying and preservation of the speci- 
mens, a small drying-house, heated by a stove, has been erected." 
