The Clouds Above Us

"How high are the clouds above the eaith's surfuce? Well, that dependa on what day or at what time you messure them," remarked Prof. Mark W. Hurri-ii;ton, director of the university observatory, last Frdy evening in response to a query ftvm a RtGl'TER reporter. "You see the clouds vary greatly n the attitude they attain. But 11] teil you one thing: I don't teheve much in these measurements that teil us that the lower side of the cloud is twelve or fourleen miles above this earth. I have been making a series of observations recentyl, and the highest cloud that I couM discover was only about three miles and a half above us. Of course the clouds extend much bigher than this, but the lower side is what I measure. 'Do you know how we figure in estimating the hight of the clouds and other things ar-ove us?" he continund. "It is all done by triangulatioD, the same method a surveyor uses when furveying cross a lake or river. There are several methods in vogue of obtaining the angles to work on, but none have proven satisfactory. Oae way has been to establish two stations about a mile apart and having the operators get the angles on the same spot of a cloud at the same instant. Havir.g the angles and the base line, it is an easy matter to figure out the hight. But the trouble in theee calculations is that the observations will not be made at eXHCtly the same instant, or that the two observers will not get the angles on the same spot in the cloud. Another method is to photograph the cloud from two different points at the same time, the same resulta being obtained as in the first method. Another trouble with this method is tbat it is almost impossible to lócate the same spot on the two negatives. S'ill another way is by taking the shadow of the cloud on the ground and triangúlate it with the sun. "All these methods are faulty, but I have recently discovered a method by which I can measure the hight of the clouds accurately and with little trouble. Perhaps you remember of reading an article some time ago regarding our being able to see the reflection of the electric Iight8 at Detroit and Ypsilanti on the clouds ahove? Well, those same electric lights at these two places have proven a boon to us and have enabled uh to make our measurements of the floa'ing bodieg by 'i very simple method. We know the dietance to Ypsilanti from the observatory to be just 5.8 miles, and to Detroit about thirty-five milec We make our observationa of the reflection of these lights on the clouds above and by trinr gulution easily dUcover their altitude. The Ypsi lanti lights being so near, the reflection is greater and more easily observed. The r fleotion of the lights at Detroit appears to be about the size of a man's hand and is not easily seen. In fact, we can make ro observation of the reflection of the Detroit lights unless the state of the atmosphere is about right. The reflection of the Detroit lights appears just above the hor zon, and neaily due east from ihe observatory. Sometimes the horizon splits the reflectien, it is so low, but we cannot make our observations then. Only when tlie cloulds are high up in the air can we see this reflection from the Detroit lights. Henee, in all our observations made on the Detroit reflection the clouds have proved to be lar higber than when we made our observations on the Ypsilanti reflection. This discovery of measuring the clouds in this method was Hke many discoveries of science, a mere chance. At first we saw nothing of importance in these reflections, but it gradually dawned upon us that there could be no better or more accurate method of measuring the height of' the clouds than by measuring this reflection. This idea had never been brought out before, but since I discovered it, I have writlen to numerous astronomers who are situated so that they can see the reflections of the lights of distant cities and they pronounce it a success in their observationg. "The results of our measurements have shown the highest altitude of any cloud so far to have been 17,580 feet above the earth's surface, and the lowest 770 feet. U8ually the clcuds are only about a ha f mile above us. "We ofien find one singular thing about the hight of the clouds - it is coniinually changing in one direction. In a series of observations made every hall hour the first measurement may show the ctauds very close to the eartn, but each sucueeding meaeurement shows them rising until by miduight they probably will have attained an altitude twice as high as the first observation shows. O', if the first observation shows the clouds high in the air, by midnight they will undountedly be much closer to the earth. They are always gradually li-ing higher or falling lower. The electric lights in thia city neither bother us or asiit us in our observations, uuless we are following a star close to the western hoiiz in. Then the light is olten too strong and interferes with cur work."