worthy Monk,—in a dream. 
1800. | 
work, 
Guido. 
This vifion is faid (I prefume like moft 
other extafies) to have been feen by the 
BRuUSH. 
from the pencil of the elegant 
Edinburgh, March 13, 1800. 
To the Editor of the Monthly Magazine. 
STR,’ 
re circumftance mentioned by G. 
A. in your Magazine for December 
dai, refpecting the effects produced by 
fowing turnips of different kinds in the 
vicinity of each other, affords a ftrong 
confirmation of the fexual propagation of 
vegetables. A fimilar fact was obferved 
here about thirty years ago by a gentle- 
man,who was accuftomed to cultivate white 
poppies. For feveral years fome poppies 
_ of the double purple kind were fuffered to 
a 
— 
*plants ? 
flower near the others, which at laft pro-. 
duced a broad dufky purple {pot in the 
centre of each petal of the white flowers. 
‘The caufe of the change being fulpe&ted, 
the purple plants were in the fubfequent 
years carefully removed, before the farina 
came to maturity, and the white flowers in 
confequence refumed their ordinary ap- 
pearance. ‘The feed of the crop of one. 
year was all along fown the fucceeding 
year without any change. 
To accumulate facts-of this kind, may 
be of ufe in a {cientific point of view, be- 
fides ferving the important agricultural 
purpofes pointed out by G. A. May it 
not, for'example, affift us in the claffification 
of plants, by ferving as a criterion to af- 
certain whether two individuals belong to 
different fpecies, or whether they are mere 
varieties of the fame {pecies? It is ge- 
merally I believe admitted, that the off- 
{pring of parents belonging to two differ- 
ent varieties of the fame fpecies of ani- 
mals can propagate ; but that when two 
individuals, of different {pecies, though of 
the fame genus, copulate, the offspring are 
real hybrids incapable of’ propagation. 
ill the fame diftinGtion hold goud , with 
fam, Sir, your humble fervant, 
Stirling, Feb. 12, 1800.' G, 
aE 
For the Monthly Magazine. 
Of the INFLUENCE of the winDs 02 the 
BAROMETER, and confequently on tbe 
MEASURING Of the HEIGHTS of PLACES 
with that INSTRUMENT.* 
(Sy M. Wid, of Milheim in Brifgau.) 
N compliance with the defire, of our 
Jt beloved prince, correfponding obfer- 
vations with the barometer and thermg. 

} 
The Influence of the Wands on the Barometer. 
335 
meter were in the courfe of the whole 
month of September, 1798, made daily at 
five different hours, at Carlfruhe by the 
privy-counfelor Bockmann, and here in 
Miulheim by me; and at, the fame time 
the ftate of wind and weather carefully 
remarked. ‘Thefe obfervations the prince 
ordered to be undertaken, with the view 
to afcertain the height of this diftriét, 
above Carlfruhe; &c.—as the knowledge 
thereof would be attended with manifeld 
advantages. Hees 
We obtained 134 obfervations, made 
with the greateft care; and from the re- 
marks relative to the wind, to which I 
here confine myfelf, I was led to conjec= 
ture, that they have a confiderable influ- 
ence on the determinations of the height 
of places by means of the ‘barometer- 
But as thefe obfervations furnifhed yet 
too many exceptions to the rule which 
feemed to be eftablifhed by the general re- 
fults of our experiments ; I was under the 
neceflity of having recourfe to other fimi- 
lar obfervations, to eftablifh the truth of 
my conjecture. i 
An opportunity of doing this occurred. 
in March 1799, in making correfponding 
obfervations at Bern and: Mulheim, for - 
the purpofe of comparing the elevations of 
different places of this diftriét with that. 
of Bern above the level of the Mediterras 
nean fea. Psofeflor Studer of Bern, an 
accurate and experienced obferver, at my 
requett, kindly undertook to make the 
correfponding obfervations in that city. 
We obtained 55 fuch obfervations, of 
which however 6 were rejected as inac- 
curate. 3 
Now here, from a comparifon of the 
winds and the heights calculated from the 
rifing or falling of the barometer and ther- 
mometer, it very, clearly appeared, that 
({uppofing the compafs divided into four. 
quarters, from North to Eaft and fo on 
to North again) the winds blowing from 
the firft quarter gave greater, and thofe 
from the thitd, {mailer elevations, when 
in both places of obfervation the’ wind 
came from the fame quarter: but if in 
ene place the wind blew from the firft, 
and in the other from the third, quarter ; 
‘we likewife obtained mean elevations. 
Of 3r obfervations, 15 were made when 
the wind blew from the third quadrant on 
three different days, and gave {mall eleva- 
tions, the fmalleft $80,1 feet, the greateft 
¢08,6;* confequently a difference of 23,55 

* Thefe and the following numbers re- 
quire fome correétion: but this does not 
affect the refults.reiative to the inflyence of 
the winds, 
only 
