Thy glass will show thee how thy beauties wear,
Thy dial how thy precious minutes waste;
The vacant leaves thy mind's imprint will bear,
And of this book, this learning mayst thou taste.
The wrinkles which thy glass will truly show
Of mouthed graves will give thee memory;
Thou by thy dial's shady stealth mayst know
Time's thievish progress to eternity.
Look what thy memory cannot contain,
Commit to these waste blanks, and thou shalt find
Those children nursed, delivered from thy brain,
To take a new acquaintance of thy mind.
   These offices, so oft as thou wilt look,
   Shall profit thee and much enrich thy book.

This is one of the sequence of climacteric sonnets, 49, 63, 77, 81, 126, 154, all of which deal with the demise of love, life, youth and beauty, either for the poet, or the beloved, or both. This one is less dramatic than the others, in that it finds an occasion for encouraging the youth to record his thoughts, for moral impovement at a later date, and does not insist that the final destruction is immanent or an object of all-pervasive fear and loathing. The tameness of the conclusion almost allows one to believe that, reading the divine offices, the breviary of former thoughts on mortality, in some quiet nook, could go on for ever and that no one need ever die.

All the sonnets bearing the climacteric numbers, which are multiples of seven or nine, show evidence of being placed purposively. They usually interrupt a set or sequence which has some unifying theme, as here, where the sequence runs from 76 to 86, apart from the interruptions of the climacteric numbers 77 and 81. The precise significance of the use of these numbers in the sonnets is unknown, although it is clear that the sonnets set at these crucial points were carefully chosen, and that their position is not the result of any accidental placing.

The 1609 Quarto Version

THy glaſſe will ſhew thee how thy beauties were,
Thy dyall how thy pretious mynuits waſte,
The vacant leaues thy mindes imprint will beare,
And of this booke,this learning maiſt thou taſte.
The wrinckles which thy glaſſe will truly ſhow,
Of mouthed graues will giue thee memorie,
Thou by thy dyals ſhady ſtealth maiſt know,
Times theeuiſh progreſſe to eternitie.
Looke what thy memorie cannot containe,
Commit to theſe waſte blacks,and thou ſhalt finde
Thoſe children nurſt,deliuerd from thy braine,
To take a new acquaintance of thy minde.
   Theſe offices,ſo oft as thou wilt looke,
   Shall profit thee,and much inrich thy booke.


1. Thy glass will show thee how thy beauties wear,
Thy glass = your mirror. The mirror seems to be used by Shakespeare in the sonnets as the touchstone of what is true. One may imagine oneself to be all manner of things, but a quick glance in the mirror brings one instantly face to face with reality. The instances in the sonnets in which Shakespeare uses glass in the sense of 'mirror' are listed below.

Look in thy glass, and tell the face thou viewest ......

Thou art thy mother's glass, and she in thee
Calls back the lovely April of her prime:

My glass shall not persuade me I am old,
So long as youth and thou are of one date;

But when my glass shows me myself indeed,
Beated and chopp'd with tann'd antiquity,

Look in your glass, and there appears a face
That over-goes my blunt invention quite, ...........

And more, much more, than in my verse can sit
Your own glass shows you when you look in it.

O thou, my lovely boy, who in thy power
Dost hold Time's fickle glass, his sickle, hour;

In the final sonnet of the beloved youth series, (126), Time itself appears to have a glass, which however is fickle. The beauties it shows do not last, and beauty itself is not to be trusted. Here in this sonnet also some of that idea is present, for the glass is beginning to show lines and wrinkles, hints of old age and of mortality.
wear - Q gives were which would give a pun with wear anyway, but the rhyme with bear does suggest that wear is the correct reading. Strictly speaking the glass does not show anyone how their beauties were (or wear), for it shows the present, not the past. It is better to have the pun the other way round. Beauty wears out and decays as clothes and other artefacts wear out and decay.

2. Thy dial how thy precious minutes waste;
Thy dial = your clock or watch face, or sundial. Possibly the reference is not to a sundial, since a sundial was more of a public instrument than a watch or clock. 'Thy sundial' and the other descriptions of looking in a glass suggest private possession of those things, and private meditation. A pocket sundial would be rather difficult to use, as one would need to know in advance in which direction to point it. However shady stealth of line 7 seems to lean more towards a sundial, as the gnomon casts a shadow from which the time was told. But a clock with its insistent ticking never ceases to tell one how the precious minutes go to nothing.
= decay, waste away, are spent and wasted.
3. The vacant leaves thy mind's imprint will bear,

The vacant leaves - the blank pages of a notebook. Or blank spaces in the book of the poet's sonnets. (See notes to following line). 

thy mind's imprint = the result of your thoughts, the words which spring from them and are written here, on these vacant leaves. imprint suggests that the mind gives its imprimatur to the things written on the vacant leaves.

4. And of this book, this learning mayst thou taste.
of this book = from this book. One has to suppose that a blank book (a table or tables, see Sonnet 122) accompanies the sonnet as a gift, or in some other way is the subject of the sonnet. It has been suggested that the glass and the dial were also a gift. At any rate some antecedent situation such as the despatch of a gift must be supposed if we are to explain the existence of the book. KDJ suggests that the book is that of the sonnets, with some blank leaves. This would help to give better meaning to the concluding couplet, which hardly makes sense as it stands. Or perhaps the youth had been given a blank book (tables) by someone else, a parent even, with a suggestion that it be filled with aphorisms and useful thoughts, as was the fashion of the time. The discussion then was to decide how to fill it, or to explain why it had lain unused for so long. Another explanation is that the blank leaves are the empty unwritten pages of the young man's mind. (See Ham.I.5.95-107, where Hamlet, as well as talking of 'his tables' also describes his mind as a book).

And thy commandment all alone shall live
Within the book and volume of my brain,
Unmix'd with baser matter:

It must be admitted, however, that the antecedent situation is unknown, and that the book may be entirely imaginary, or it may be a gift of tables (a blank book), or a gift of the poet's sonnets, or something already in the youth's possession.

this learning = the thoughts which your mind commits to the book.
mayst thou taste
= you will be able to enjoy, sample, mull over.

5. The wrinkles which thy glass will truly show
This quatrain expands the thought of lines 1-2. The first two lines tell the youth what his glass will show him, and what that implies. Similarly for 7-8, which return to the observations of the dial. The wrinkles - lines in the forehead and elsewhere on the face.
6. Of mouthed graves will give thee memory;
mouthed graves - graves were often described as gaping. As in
O braggart vile and damned furious wight!
The grave doth gape, and doting death is near;
Wrinkles themselves are visually not much like gaping graves, but they remind the possessor that old age, death and burial are near at hand. mouthed has the final ed pronounced.
give thee memory
= remind you, bring to your memory, give you a reminder.
7. Thou by thy dial's shady stealth mayst know
dial's shady stealth - if a sundial is referred to, the shadow of the gnomon moves imperceptibly, hence stealthily. The hand(s) on a clock face could also be meant. They cast a shadow on the face, and move imperceptibly.
8. Time's thievish progress to eternity.
The stealthy movement of the shadow on the dial, or the hands over the face of the clock is reminiscent of the stealthy movement of a thief, who seeks not to be discovered.
9. Look what thy memory cannot contain,
Look what = whatever. See 9.9 and 11.11 for a similar use.
10. Commit to these waste blanks, and thou shalt find
Commit to = write down on, entrust to.
waste blanks
= empty sheets of paper. The emendation of Q's reading blacks to blanks is generally accepted.
11. Those children nursed, delivered from thy brain,
Those children (thoughts), which were born (delivered) from your brain, have been nursed and looked after (by this book).
12. To take a new acquaintance of thy mind.
Observations made in times past (children of your brain) will newly acquaint themselves with you, when you have an opportunity to scan these leaves in future years.
13. These offices, so oft as thou wilt look,
These offices = these exercises, or duties of observing the clock's face or the mirror's reflection, and noting them down. Possibly the office or duty is that of reading the book now filled with his observations. A sideways glance is also probably intended at the religious practice of reading offices (prayers) at fixed times of the day from the breviary.
14. Shall profit thee and much enrich thy book.
and much enrich thy book - the enriching of the book (if it is a blank book) is presumably done by writing observations in it. Here it is suggested that merely looking in it enriches it. If it is totally blank, then looking on blank leaves is a totally fatuous exercise and enriches neither observer nor observed. The looking however could be in the glass or the dial, and making philosophical observations thereon. KDJ suggests that the book is the book of the poet's sonnets, which will have blank spaces and pages in it, and that the poet's self-effacement allows him even to pretend that his sonnets are so many empty lines, leaving the pages blank. Nevertheless his thoughts filter through in some way, and the youth couples them with his own thoughts on mortality, thus enriching the book and his experience at the same time.
The meaning and setting of the sonnet, however, because we are uncertain of the nature of 'thy book', remains rather mysterious.