THE PRACTICAL OUTCOME OF SCIENCE. 481 



merit became alarmed at the fearful destruction of ship timber in 

 its dock-yards by a minute boring beetle, and applied to him for 

 a remedy. He replied that the beetle which laid the eggs only 

 appeared in the month of May, and that by submerging the tim- 

 ber during that period it could be protected from its ravages. 

 The Government did so, and thus not only saved its timber at an 

 insignificant expense, but also brought the derided bug-hunter 

 into respect, as one who had demonstrated the practical utility of 

 his apparently visionary study. 



Researches upon the properties of laughing-gas and ether and 

 investigations relating to the peculiarities of infusorial life also 

 exhibit knowledge which at first appeared absolutely worthless, 

 but was afterward found to be exceedingly practical. Students 

 originally took ether for fun, and laughing-gas fell to the level of 

 a wonder exhibited by itinerant lecturers ; yet out of that knowl- 

 edge was destined to come our modern discovery of anaesthesia, 

 by which surgical operations may be performed without pain and 

 without the knowledge of the sufferer. In like manner the re- 

 searches upon the infusoria, from the time of Leuwenhoek to 

 Ehrenberg, had apparently no practical value, yet from their dis- 

 coveries have been developed a truer form of one of the most im- 

 portant practical doctrines of modern chemistry, a modification of 

 the practice of medicine, a revolution of the science of surgery, an 

 application of new and more correct ideas in matters pertaining 

 to agriculture ; and, combined with all this, remains the proba- 

 bility that their power for usefulness is not yet exhausted. 



For the sake of illustrating the difference between the prac- 

 tical man and theorist, let us suppose two persons to visit the 

 northern peninsula of Michigan seeking for iron. The one runs 

 along blindly, takes up with every good show, and mines. The 

 result is, he either makes a happy strike by mere accident, or 

 spends thousands of dollars in useless search. The other has 

 studied the laws of electricity, and knows that certain ores of iron 

 are magnetic. He understands also that these ores will exert 

 their influence through any amount of superincumbent earth. 

 Consequently he provides himself with a dipping-needle and com- 

 pass, and by the operation of these tells where a bed is located, its 

 approximate depth, and probable amount of material. To prevent 

 being deceived by the magnetic schists in that region, by means 

 of his dipping-needle and compass he traces up the bed until he 

 finds an outcrop. Thus have been located, at little expense, many 

 of the mining regions of that locality. What an achievement is 

 this, and how much better than the blind guesses of the so-called 

 practical man ! 



The history of that wonderful piece of mechanism, the steam- 

 engine, furnishes another illustration of a different character. In 



