[ ICO ] 
1845 Trillium flore pedunculato cernuo, Lin. Sp. 
PI- 339- 
1846 Valeriana montana fubrotundo folio, C. B. P. 
1 6f. 
1847 Vicia pedunculis multifloris, petiolis polyphil- 
lis, foliolis lanceolatis glabris, Hort. Upfal, 
2 19. 
1848 Vicia fylvatica multiflora maxima perennis, 
tetro odore, floribus albentibus, lineis casru- 
leis ftriatis, Pluk. Aim. 387. 
1849 Vinca foliis oblongo-ovatis integerrimis, tubo 
floris longiffimo, caule ramofo fruticofo. 
Miller’s Iconf. 
i8yo Xanthium, five Lappa minor, J. B. 3. 572. 
Lappa minor, five Xanthium Diofcorid. C. 
B. P. 19S. 
XVIII. An experimental Enquiry concerning 
the natural Powers of Water and Wind to 
turn Mills , and other Machines , depending 
on a circular Motion . By Mr . J. Smeaton, 
F, R. S. 
Read May 3, 
& 10, 1759. 
W HAT I have to communicate on 
this fubjedt was originally deduced 
from experiments made on working models, which 
I look upon as the befl means of obtaining the out- 
lines in mechanical enquiries. But in this cafe it 
is very neceffary to diflinguifh the circumflances in 
which a model differs from a machine in large; 
otherwife a model is more apt to lead us from the 
truth 
