[ 1 
fpryata. AaguUis igitur EH A erit incf.otnei;mai 
metri luns ob ipfiiis atmolpliasratn : Sed angulue 
EHA opponituf lateri EA rrianguli EH Ah an- 
gulus AEH (upplcmQfitum ad i8o'^ refjiaifiionis iao- 
rizontalis in ^tmo/phaira lunari oppoiiitur lateri 
AH diftantiae lunas a terra. Porro latus EA nae- 
dietas ed cliordas atmorphaerse lunaris iplius luna: cor- 
pus in A tangentis. Sinus ergo incrementi EAH 
diaraetri lunac ob ipfius atmofphsram erit ad finum 
fupplementi refra^Uonis horizontalis A EH, ut me- 
dietas AE chords atmofphaira: corpus Lun^ tan- 
gentis ad diftantiam AHlmix a terra. 
Hinc fequitur plane inrenfibile evadere illud dia- 
metri lunaris incrementum : Si enim ad 2" j afl'ur* 
geret, fuppofita refradUone horizontali f', id eft, tri- 
ginta faltem vicibus majori, quam fupponi potcft, ut 
ex infra dicendis patebit j femichorda 276 leucas 
Gallicas xquaret^ atmolph^erseque terreftris chordam 
fimilem longe fuperarer. Luna igitur atmofphaera 
cingatur, necne, eadem Temper obfervabitur ejus dia- 
meter} nulloque modo diamctri lunaris oblervatio 
folvend^ quaeftioni par cfte poteft. 
Pig. 2. Majorem decidendi dpbii anfam prxbent 
eclipfes folis a luna ; Radii enim extremi conum um- 
brae lunaris terminantes, utpote qui corpus lunas ftrin- 
gunt, Sc ejus atmofphaeram pertranfeimt, neceflario 
yerfus coni axem inflcdentur; ideoque brevior & 
obtufior conus evader ; ut autem illius variationis 
quantitas innotefcar, notandum eft radium EA, feu 
ipfi parallelum EG, qui, fi nulla exifteret armo- 
fphacra, umbra; lunaris EAC terminus eflet, in ipfo 
atmofphxrae ingreftu G, Sc m egreftu H, verfus axem 
GA, refringi ; unde femiangulus coni unihra; lunaris 
L 1 2 quan- 
