372 Rarified Air Balloons. 
tween its minute molecules ; but merely adheres to the sure 
face of each fragment. 
| will add a cireumstance which has been overlooked by 
the great chemists of Europe. Prof. Beck and myself, on 
making particular inquiry of several hundreds of Mr. Van 
Rensselaer’s tenants, learned this curious fact ; that where- 
ever the soil was of that character which disengages the roots 
of winter wheat, which is called by farmers “ winter-killing,” 
most remarkable, the time of such suspension did not wholly 
depend on the proportion of alumine ; for where the propor- 
tion was the same in two specimens of soil, there was often a 
great difference in this property. By a minute attention to 
this subject, we were enabled to establish this rule for the 
direction of the agriculturist. Jf his soil will settle in four 
hours, after being well stirred ina tumbler == poet water, he 
need have no apprehensions of the * winte. it 
remains turbid over four hours, and under ne the danger 
4s not very great. But soils which remain turbid from twelve 
to twenty eo seus are not safely sown with wheat. 
ou Amos EATON. 
eensinlion "School, Troy, 
April 27, 1927. 3 
eke sat Be Air Balloons.—In a course of experimentat 
s, before the college classes in chemistry and natu- 
ral sbilossphy, Prof. AnBor and myself had occasion to pre- 
pare a rarified air balloon. We adopted two or three expe- 
dients for causing it to ascend more surely and higher, whieh 
{ have not seen mentioned, and which may be worth the at- 
tention of = ay who may wish to construct balloons of this. 
descripti 
"The b <a was twelve feet in diameter and spherical, with 
an opening between three and four feet, at its lower pole. 
To the edge of this opening, which was made strong by a 
wooden hoop, we fastened a piece of cambric, with a tape 
a. through the opposite edge, so that it could be almost 
— rawn or puckered up, when the balloon was in- 
= Hi aving effected this by burning baked straw, dipped 
_we closed the — and thus prevented the 
escaping. It rose very majestically about 
3 400 or 309 oer and answered our expectations, except that 
