SOURCE: This comes from the Latin translation that accompanies De Furia's edition of the Greek Aesopic corpus, published in 1810 and available at GoogleBooks. This is fable 255 in De Furia; for other versions, see Perry 103.
READ OUT LOUD. Choose which marked text you prefer to practice with - macrons or accent marks - and read the text out loud until you feel comfortable and confident. Then, try reading the unmarked text at the bottom. It should be easy for you after practicing with the marked texts. :-)
MACRONS. Here is the text with macrons:
Iuppiter Mercuriō imperāvit, ut artificibus omnibus mendāciī pōtiōnem conficeret. Ipse, singulīs quae ad id opus erant pistillō contūsīs, atque mēnsūrā prō ratiōne miscendī confectā, universis aequālem pōtum praebuit. Cum vērō, sūtōre sōlō relictō, multum adhuc ex pōtiōne superesset, Mercurius, mortāriō arreptō, tōtum illī bibendum dedit; atque contigit inde, ut artificēs omnēs mendācēs sint, maximē vērō omnium sūtōrēs.
ACCENT MARKS. Here is the text with accent marks, plus some color-coding for the words of three or more syllables (blue: penultimate stress; red: antepenultimate stress):
Iúppiter Mercúrio imperávit, ut artifícibus ómnibus mendácii potiónem confíceret. Ipse, síngulis quae ad id opus erant pistíllo contúsis, atque mensúra pro ratióne miscéndi confécta, univérsis aequálem potum praébuit. Cum vero, sutóre solo relícto, multum adhuc ex potióne superésset, Mercúrius, mortário arrépto, totum illi bibéndum dedit; atque cóntigit inde, ut artífices omnes mendáces sint, máxime vero ómnium sutóres.
UNMARKED TEXT. Here is the unmarked text - after practicing with the marked text that you prefer, you should not have any trouble with the unmarked text:
Iuppiter
Mercurio imperavit,
ut artificibus omnibus
mendacii potionem conficeret.
Ipse,
singulis
quae ad id opus erant pistillo
contusis,
atque mensura
pro ratione miscendi confecta,
universis
aequalem potum praebuit.
Cum vero,
sutore solo relicto,
multum adhuc ex potione
superesset,
Mercurius,
mortario arrepto,
totum illi bibendum dedit;
atque contigit inde,
ut artifices omnes
mendaces sint,
maxime vero omnium
sutores.
IMAGE. Here is an illustration for the story (image source) showing an ancient Greek shoemaker:
Here is another illustration from the Medici Aesop, which is online at the New York Public Library website.