May 25, 1900.] 



SCIENCE. 



833 



and Mr. Clayton points out that observations 

 in the high regions of the atmosphere afford 

 criteria for determining which of the four types 

 of instability is most predominant in a cyclone. 



The kite observations at Blue Hill seem to 

 show according to Mr. Clayton that the first 

 type of instability is not all important, but it 

 must be remembered that these kite observa- 

 tions do not extend beyond 3000 meters above 

 sea level, and although Mr. Clayton considers 

 also the balloon observations which have been 

 made in Europe, still we think that his conclu- 

 sion is more or less tentative (as no doubt Mr. 

 Clayton intends it to be) but he seems to lose 

 sight of the fact that the vertical stability 

 theory, No. 1, requires a high pressure area in 

 the higher regions to be directly above a low 

 pressure area at the earth's surface. Thus Mr. 

 Clayton seems to think that the observations of 

 March 24, 1899, showing a low pressure area 

 near the earth's surface in Italy and a low pres- 

 sure area in the upper air over Finland, is 

 against the vertical instability theory. Fur- 

 ther, after a cyclone has been some time under 

 way the upward current near the center of the 

 cyclone would undoubtedly produce a mass of 

 warm air extending to enormous altitudes im- 

 mediately above the center and that, therefore, 

 the absence of a cold stratum within the range 

 of the observations is not decisively against the 

 vertical instability theory. 



Furthermore, the force of Dr. Hanu's ob- 

 jection to the preponderating influence of the 

 third type of instability, that cyclones are more 

 frequent and more violent in winter than in 

 summer, is weakened by the fact that our posi- 

 tion with reference to the polar and equatorial 

 winds is very different in winter than it is in 

 summer so that the influence of the fourth type 

 of instability is greatly different at these two 

 seasons and may mask the effect of the third 

 type. 



The probability is that one type of instability 

 may preponderate in one place or one season 

 and another type in another place or season. 



The present writer is inclined to think that 

 as a rule, the first type of instability furnishes 

 the energy of cyclonic movement and that the 

 fourth type determines the line of progress or 

 the path of the cyclone ; that the second type 



of instability is the cause of the local disturb- 

 ances which occur in the region just ahead of a 

 cyclone such as tornadoes and thunder storms ; 

 and that the third type of instability contributes 

 greatly to the violence of these local disturb- 

 ances. 



W. S. F. 



APPLIED SCIENCE IN MUNICIPAL WORK. 



The city of Marshalltown, Iowa, has just is- 

 sued in pamphlet form, the 'preliminary data 

 for the design of a proposed sewage system ' 

 which illustrates in an unusually satisfactory 

 manner, the rare case in which municipal au- 

 thorities have displayed enough of wisdom and of 

 familiarity with the resources of their country 

 to bring to -bear upon their problems of con- 

 struction, the best scientific knowledge avail- 

 able. The committee of the city council applied 

 to Professor Marston, the civil engineer, Pro- 

 fessor Weems, the chemist and Professor Pam- 

 mel, the botanist of the University of Iowa, for 

 advice, and under their direction the data 

 reported were collected. The work of the 

 survey in detail, was done by trained students, 

 largely, and the drawings were made by Miss 

 Wilson. The city of Marshalltown paid all ex- 

 penses and its oflBcials seem to have heartily 

 seconded the endeavor of the chemists and en- 

 gineers of the University. 



The city has a population of 12,000 and is 

 the county seat of Marshall Co. , and the com- 

 mercial center of a rich agricultural country. 

 There is some manufacturing, the principal 

 shops of the Iowa Central Railroad and large 

 beet-sugar manufacturing establishments being 

 located there. The sewer system contains 

 about ten miles of sewers and laterals. Water 

 is supplied from drive-wells and to the amount 

 of about 1,300,000 gallons per day, the glucose 

 and packing houses taking a large fraction of 

 that used for other than domestic purposes. It 

 contains about 300 parts solid matter in the 

 million, mainly lime and magnesia salts. 

 Deeper wells of artesian character, belonging 

 to the glucose company, show about 900 parts 

 solid matter, of which about two-thirds seem 

 to be lime and magnesia salts and fifteen per 

 cent, organic matter, although the wells are 

 300 feet in depth. The city water in May, 1899, 



