390 Researches into the Anatomy of Plants. 
surface of the glasses less concave * than he did at first, so 
that whatever light may enter the eye after reflection is no 
longer brougkt to a focus, and consequently is not per- 
ceived. We have then a larger field of view than with 
common spectacles, without introducing any new inconve- 
nience. 
During the Jast three months M. Cauchoix has made 
trial of these spectacles on a great number of persons, and 
even upon one so short-sighted that he could not see be- 
yond 24 inches, which is certainly a case of extreme short- 
sightedness. All these persons agree in making the same 
favourable report. The trials made by elderly persons re- 
quiring the assistance of convex glasses have also been at- 
tended with just the same success. 
Iam the more particular in noticing these trials of some 
months continuance, because it is by continued trial alone 
that we can be certain of the goodness of spectacles, and in 
eneral of optical instruments that do not magnify much. 
he eve has a certain flexibility, and power to accommodate, 
itself for a short time to a glass that does not quite suit it. 
But if the same degree of effort is to be long continued the 
eye tires, and complains of an imperfection that was not 
at first perceptible. 
It appeared to me that so decided an improvement upon 
an instrument generally used, and indeed so necessary to 
many persons, deserved some public notice; and I advise 
those who ever use spectacles to make trial of these. If 
they are as well satisfied as I have reason to expect, they 
will derive a further pratification from reflecting that the 
science which thus adds to our enjoyment of the objects 
immediately around us, is the same that has made us ac- 
quainted with the remotest parts of our solar system, and 
given us some conception of the extent of the universe. 
(Signed) Brot, 
Member of the lmperal !ustitute. 
LXIII. Researches into the Anatomy of Plants. By 
Hi. F, Link, of Breslau, formerly of Rostock. 
(Continued from p, 282.] 
Il. The Vessels of Plants, 
Osservarions frequently and carefully repeated have in- 
duced me to abandon the theory of the moderns, as to 
the, yessels of plants, and to follow that of the naturalists 
*. As they have been-made from the first by Messrs. Dollond. h 
whe 
