Try the experiment
“They are trying the experiment of running railroad trains by electricity.” This should be, “They are making the experiment,” etc. The word experiment contains the idea of trial, hence, to try the experiment is to try the trial.
Little piece
“I will go with you a little piece.” A short distance or a part of the way would be more appropriate.
Every confidence
“I have every confidence in his ability to succeed.” Confidence is a unit; every implies several units considered separately. “I have the greatest confidence in his ability to succeed” is correct.
Ugly
This word properly applies to the appearance of a person or thing, hence such expressions as “He has an ugly temper,” “This is an ugly customer,” “That was an ugly rumor,” etc., although common in colloquial discourse, should be avoided in dignified address.
This is a provincialism that should be avoided. Use unknown.