| books that make one drowsy".

17. Univ. is "men". The Subject is evidently "a man who knows what he's
about"; and the word "when" shows that the Proposition is asserted of
_every_ such man, _i.e._ of _all_ such men. The verb "can" may be
replaced by "are men who can".

The Proposition may be written

"All | men who know what they're about | are | men who can detect a
sharper".

18. The Univ. and the Subject are the same as in Ex. 4.

The Proposition may be written

"All | Members of the Class 'you and I' | are | persons who know
what they're about".

19. Univ. is "persons". The verb "wear" may be replaced by the phrase
"are accustomed to wear".

The Proposition may be written

"Some | bald persons | are | persons accustomed to wear wigs".

20. Univ. is "persons". The phrase "never talk" is merely a stronger
form of "are persons who do not talk".

The Proposition may be written

"All | fully occupied persons | are | persons who do not talk about
their grievances".

21. Univ. is "riddles". The phrase "if they can be solved" is equivalent
to the Attribute "that can be solved".

The Proposition may be written

"No | riddles that can be solved | are | riddles that interest me".

Sec. 2.

_Method of Diagrams._

_Solutions for Sec. 4, Nos. 1-12._ SL4-A

.---------------. .-------.
1. No m are x'; | | (O)| | | |
All m' are y. | .---|---. | |---|---|
| | | | | | |(O)|
|(I)|---|---|---| .-------.
| |(O)|(O)| |
| .---|---. | .'. No x' are y'.
| | (O)|
.---------------.
pg137
.---------------. .-------.
2. No m' are x; |(O) | (O)| | | |
Some m' are y'. | .---|---. | |---|---|
| | | | | | |(I)|
|---|---|---|---| .-------.
| | | | |
| .---|---. | .'. Some x are y'.
| | (I)|
.---------------.

.---------------. .-------.
3. All m' are x; |(O) | (I)| | |(I)|
All m' are y'. | .---|---. | |---|---|
| | | |