FRAGMENTS OF SCIENCE. 



137 



tirely different kinds; and the woodpecker 

 and warbler in the tree tops select still oth- 

 er?. The practical value of birds in control- 

 ling insect pests should be more generally 

 recognized. It may be an easy >matter to 

 exterminate the birds in an orchard or grain 

 field, but it is an extremely difficult one to 

 control the insect pests. It is certain, too, 

 that the value of our native sparrows as 

 weed destroyers is not appreciated. Weed 

 seed forms an important item of the winter 

 food of many of these birds, and it is im- 

 possible to estimate the immense numbers 

 of noxious weeds which are thus annually 

 destroyed. If birds are protected and en- 

 couraged to nest about the farm and garden, 

 they will do their share in destroying noxious 

 insects and weeds ; and a few hours spent in 

 putting up boxes for bluebirds, martins, and 

 wrens will prove a good investment. 



Kites and Balloons in Meteorology. 



The recent development of the kite for me- 

 teorological purposes, Mr. A. Lawrence Roche 

 says in his paper on the subject, has taken 

 place in the United States, while the use of 

 automatic balloons for obtaining data at very 

 great altitudes has hitherto been confined to 

 Europe. Kites appear to have been first ap- 

 plied in meteorology by Alexander Wilson 

 in Glasgow, who in 1*749 raised thermome- 

 ters attached to them into the clouds. Next 

 was Franklin's electrical experiment. Be- 

 tween 1883 and 1885 E. D. Archibald made 

 differential measurements of wind velocity 

 by anemometers raised on kites fifteen hun- 

 dred feet. In 1885 A. McAdie repeated 

 Franklin's experiment on Blue Hill ; and he 

 afterward made other electrical experiments 

 with kites. The invention of light-weight 

 self-recording instruments made it possible 

 to obtain graphic records in the air by means 

 of kites ; and the introduction of tailless 

 kites by Mr. Eddy added to their usefulness. 

 The thermograph raised by S. P. Ferguson, 

 of Blue Hill, in August, 1894, was no doubt 

 the first instrument recording continuously 

 and graphically to be raised by kites ; and 

 it permitted simultaneous observations to be 

 obtained in the free air and near the ground. 

 This method of studying the meteorological 

 conditions of the free air has ever since been 

 in regular use at the Blue Hill Observatory. 

 Probably the greatest elevation yet attained 



by kites, and certainly the highest level to 

 which kites have lifted a meteorograph, is 

 8,740 feet above Blue Hill. This was ac- 

 complished October 8, 1896, by the aid of 

 nine kites, having a total area of 170 square 

 feet, which gave a maximum pull at the 

 ground of about a hundred pounds. The 

 meteorograph remained during several hours 

 higher than a mile, and good records of the 

 indications of the barometer, thermometer, 

 and hygrometer were brought down. More 

 than one hundred records of atmospheric 

 pressure, temperature, and relative humidity 

 of the air, or wind velocity at intermediate 

 heights up to the extreme altitude mentioned 

 have been obtained. Kites furnish a ready 

 and accurate method of measuring the heights 

 of certain low and uniform clouds. Changes 

 of wind direction in the different air strata 

 are determined from the azimuths of the 

 kites. To reach much higher altitudes than 

 three miles unmanned free balloons have 

 been considerably used in France and Ger- 

 many. These balloons, which carry self- 

 recording apparatus, rise until equilibrium is 

 attained in the rarefied air, when they lose 

 their buoyancy and fall to the earth. Most 

 of them have been recovered, with the in- 

 struments and records uninjured. 



The Education of an Engineer. Criti- 

 cising the present methods of education, 

 especially for qualifying students in mechan- 

 ical science, Mr. G. F. Deacon asked, in his 

 British Association sectional address, "Are 

 we not in some cases attempting, at too 

 early a stage, the teaching of subjects in- 

 stead of principles ? I mean including the 

 practical working of details which will be- 

 come the regular work of the student in the 

 office or works of an engineer. ... I do not 

 say that subject training of this kind at col- 

 lege may not be useful ; but we have to con- 

 sider whether it does not, for the sake of 

 some little anticipation of his office work, 

 divert the attention of the student from the 

 better mastery of those principles which it is 

 so essential for him to grasp at the earliest 

 possible time, and which do not limit his 

 choice in the battle of life to any branch 

 whatever of the profession or business of an 

 engineer, but which, on the contrary, qualify 

 him better to pursue with success whatever 

 branches his inclination or his opportunities 



