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THE NATIONAL GEOGRAPHIC MAGAZINE 



Then, as you approach the shore you 

 should get resonance effects, like those 

 perceived when you shout out loudly in 

 an empty cave. 



However, I must not take up your time 

 in speaking upon only one subject. What 

 I want to direct your attention to is that 

 both discovery and invention are not 

 things that come all at once. They arise 

 from very simple beginnings. A small 

 observation, patiently followed up by 

 other observations equally small, leads 

 gradually to a big conclusion. Do not 

 ignore little things; life itself is made up 

 of them, and there is a good old Scotch 

 saying that bears upon the point : 



"Mony a mickle maks a muckle." 



A great many small things make a big 

 one. Any one, if he will only observe, 

 can find some little thing he does not 

 understand as a starter for an investiga- 

 tion. 



AN EXPDRIMKNT AT HOME: 



I had rather a curious illustration of 

 this the other day in my own house. I 

 told a lad who was waiting upon me that 

 I wanted to make some experiments with 

 a bottle of water, and told him to bring a 

 bottle of very hot water from the kitchen, 

 and be sure that it was quite full. He 

 soon returned with a big-bodied bottle 

 provided with a long and narrow neck, 

 filled to the brim, and put it on the man- 

 telpiece and went downstairs. After the 

 water had cooled, I rang the bell for 

 John. 



"John," I said, "I thought I told you. 

 to fill that bottle quite full." 



"So I did, sir," he replied. 



"Well, look at it now ; it's not nearly 

 full ; the neck is quite empty." 



John assured me that he had not 

 touched the bottle since he first put it up, 

 and I assured him that I had not poured 

 any of the water out. 



"Well," I said, "what has become of 

 the water?" 



He was quite nonplussed at first, and 

 then he began to — to — ratiocinate, and 

 said : "The water was quite hot when I 

 put it in; there was steam coming from 

 it. The water must have evaporated." 



I made no comment, but looked at him 

 and said: "Let's try it again. You fill 



that bottle chock full of hot water this 

 time, and then cork it so that no steam 

 can escape." 



He did so ; and by and by I rang the 

 bell again, and up came John. 



"John," I said, "I thought you filled 

 that bottle quite full." 



"So I did, sir," he replied. 



"Well, look at it now ; it's not nearly 

 full." John assured me that he had not 

 touched the cork, and I replied : "Well, 

 what has become of the water?" John 

 said he didn't know. He admitted that 

 some of it had evidently gone, but where 

 it had gone he couldn't for the life of him 

 conceive, and he hasn't found out yet. 



I am sorry now I didn't think of telling 

 John to weigh the bottle when he first 

 brought it up, for by weighing it again 

 he could have found out exactly how 

 much had disappeared. 



If John hadn't given up he might have 

 arrived by degrees at a realization of the 

 principle upon which a thermometer 

 works. 



A thermometer is an instrument for 

 measuring heat, and whenever you can 

 measure a phenomenon you have a basis 

 upon which may be built a science ; in 

 fact, all science is dependent upon meas- 

 urement. 



When you measure heat you get the 

 science of thermo-dynamics, and thermo- 

 this and thermo-that. When you meas- 

 ure the pressure of the atmosphere by a 

 barometer you lay the basis for the 

 science of meteorology and a whole lot 

 of sciences dependent upon atmospheric 

 measurements. So you have sciences 

 based upon the measurement of sound 

 and light ; but you have no science of 

 odor. 



MEASURING AN ODOR 



Did you ever try to measure a smell? 

 Can you tell whether one smell is just 

 twice as strong as another. Can you 

 measure the difference between one kind 

 of smell and another. It is very obvious 

 that we have very many different kinds 

 of smells, all the way from the odor of 

 violets and roses up to asafetida. But 

 until you can measure their likenesses 

 and differences you can have no science 

 of odor. If you are ambitious to found 

 a new science, measure a smell. 



