Absent fraud, §23-2-29. Mere ignorance of law, §23-2-27. Mistake in judgment of value, §23-2-28. 564 INDEX EQUITY —Cont’d Accident and mistake —Cont’d Interference of equity not authorized —Cont’d Mutual ignorance of fact, §23-2-28. Volunteers in general, §23-2-33. Judgment of value, §23-2-28. Mistake, §23-2-28. Power exercised cautiously, §23-2-21. Mistake of law or fact, §23-2-21.