1 42 Mr. edgewor 1 k’s Experiments upon 
way ; but, as a more complicated apparatus than I could at 
prefent procure is neceffary for this purpofe, I determined to 
offer you the flight progrels I have made, in hopes that fome 
gentleman, more converfant and more interefred than myfelf 
in thefe inquiries, maypurfue them with fuccefs and advantage 
to the public. I fhall only remark, that the general caufe of the 
different refinance of the air upon furfaces of different fhapes, 
is the flagnation of that fluid near the middle of the plane 
upon which it ftrikes. The fhape and fize of the portion thus 
flagnated, differs from the fhape and angle of the plane. The 
elaff icity of the air permits the parts in motion to comprefs 
thofe which are firfl flopped or retarded by the plane, and 
forms, as it were, a new l'urface of a different fhape, for the 
reception of thofe particles which lucceed. With the afliflance 
of a good folar microfcope the curves of the air flriking againfl 
different furfaces may be delineated, and when the general fa£ls 
are once clearly afcertained, mathematicians will have an ample 
field for curious and ufeful fpeculation. 
TABLE. 
