re is a little doubt whether the meaning is "_since_ they are,
or, _if_ they are, unaccompanied."

*That or when.*--"Men _walking_ (_that_ walk, or _when_ they walk) on
ice sometimes fall."

It is better to use "men walking" to mean "men _when_ they walk." If
the relative is meant, use "men that walk," instead of the participle.

(1) "_While_ he was } _Walking_ on { (1) the road, } he fell."
(2) "_Because_ he was } { (2) the ice, }

When the participle precedes the subject, it generally implies a
cause: "_Seeing_ this, he retired." Otherwise it generally has its
proper participial meaning, _e.g._ "He retired, _keeping_ his face
towards us." If there is any ambiguity, write "_on_ seeing,"--"_at the
same time_, or _while_, keeping."

(1) "_Though_ he was} {(1) he nevertheless stood
} { his ground."
(2) "_Since_ he was } _Struck_ with terror, {(2) he rapidly retreated."
(3) "_If_ he is } {(3) he will soon retreat."

*8. When using the Relative Pronoun, use "who" and "which" where the
meaning is "and he, it, &c.," "for he, it, &c." In other cases use
"that," if euphony allows.*

"I heard this from the inspector, _who_ (and he) heard it from the
guard _that_ travelled with the train."

"Fetch me (all) the books _that_ lie on the table, and also the
pamphlets, _which_ (and these) you will find on the floor."

An adherence to this rule would remove much ambiguity. Thus: "There
was a public-house next door, _which_ was a great nuisance," means
"_and this_ (_i.e._ the fact of its being next door) was a great
nuisance;" whereas _that_ would have meant "Next door was a
public-house _that_ (_i.e._ the public-house) was a great nuisance."
*"Who," "which," &c. introduce a new fact about the antecedent,
whereas "that" introduces something without which the antecedent is
incomplete or undefined.* Thus, in the first example above,
"inspector" is complete in itself, and "who" introduces a new _fact_
about him; "guard" is incomplete, and requires "_that_ travelled with
the train" to complete the meaning.

It is not, and cannot be, maintained that this rule, though observed
in Elizabethan English, is observed by our best modern authors.
(Probably a general impression that "that" cannot be used to refer to
persons has assisted "who" in supplanting "that" as a relative.) But
the convenience of the rule is so grea