The engineers, surveyors and other persons employed by and acting for said survey, and all such persons employed by and acting for the United States geological survey, or other department of the United States government, having for their purposes the obtainment and diffusion of practical information relating to the resources and development of the state, the advancement of science, and the carrying out of the objects of the state geological and economic survey, shall have the right to enter upon all lands, either public or private, and into all mines, for the purpose of exploring, surveying, or doing any other thing which may be necessary to effect such objects, and examine any property, products or developments, relating to the objects of said survey, within the state, without molestation or arrest, and without being liable to the owners thereof, except for actual damages done to the property.