66 



SCIENCE 



[N. S. Vol. XXVIII. No. 707 



ments with Tar and Oil on the Highways 

 of Rhode Island." It divided highways 

 into three classes, interstate trank lines 

 and popular routes of travel, highways 

 connecting towns which are only a few 

 miles apart and secondary streets of towns, 

 and third, feeders leading to towns and 

 highways of the two preceding classes and 

 those connecting towns which are many 

 miles apart. 



The objects of the experiments with tar 

 and oil have been to reduce to a minimum 

 the amount of dust raised by motor-cars, 

 preserve the surface of the road, and to 

 increase its life. The total cost per square 

 yard of tar-macadam on the Post Road be- 

 tween New York and Boston, and in the 

 Town of Charlestown, in 1906 and 1907, 

 was $0.1624. The amount of tar used per 

 square yard was 1.15 gallons. It was 

 found that the different samples of tar and 

 oil used had compositions which were de- 

 cidedly different. 



Judging from the results of the experi- 

 ments so far made, it is evident that addi- 

 tional experimental work should be done 

 (1) to determine the relation of the com- 

 position of tar to the efficiency of a tar- 

 macadam road and tar-painting; (2) to 

 compare the efficiencies of tar-macadam 

 roads constructed by the mixing and pene- 

 tration methods; (3) to determine the 

 economic value of scarifying, reshaping 

 and reconstructing the surface of old 

 macadam roads by the addition of tar by 

 the penetration method; (4) to discover 

 methods of increasing the bond between the 

 tar-matrix and the surface of the old ma- 

 terial of the road; (5) to determine the 

 efficiencies of the various machines on the 

 market for spreading tar and for making 

 the roads; and (6) the efficiencies of the 

 roads treated with the various oils on the 

 market, and in different ways. The au- 

 thor firmly believes that more stress 

 should be laid on the economic construction 



of more permanent macadam roads and 

 that less attention should be paid to the 

 various surface palliatives. The paper 

 was published in the Engineering Record 

 for February 8, 1908. 



The subject of the "Pressure-Tempera- 

 ture Diagram of the Properties of Super- 

 heated Steam" was discussed and illus- 

 trated by Henry T. Eddy, professor of 

 mathematics and mechanics, University of 

 Minnesota. He showed that for purposes 

 of both instruction and use the "P-T" 

 diagram offered certain advantages over 

 the "P-V" diagram which is usually used, 

 and more especially in showing the varia- 

 tions in the specific heat of superheated 

 steam. 



A paper descriptive of "An Instrument 

 for Investigating the Circulation of Water 

 in Water-tube Boilers ' ' was read by Frank 

 C. Wagner, professor of experimental 

 engineering. Rose Polytechnic Institute, 

 and was discussed at some length by those 

 present who had made similar experiments. 



"A Note on the Shearing Stresses in 

 Beams" was presented by Calvin M. 

 Woodward, professor of mathematics and 

 applied mechanics, Washington University, 

 and discussed by several members. 



The same author read a paper on "The 

 Problem of Power for Airships," which 

 was discussed very fully by the members. 



An elaborate paper on the "Classifica- 

 tion and Comparison of Hydraulic Tur- 

 bines as to Performance at Best Speed," 

 and illustrated with tables was read by 

 Benjamin F. Groat, professor of mechanics 

 and mathematics. University of Minnesota. 



The same author presented a valuable 

 paper on the "Efficiency of the Screw." 

 These two papers add much to the respect- 

 ive subjects and should be put into perma- 

 nent form for future reference, being too 

 long to be abstracted satisfactorily. 



In the absence of the authors, the fol- 

 lowing papers were read by title: "The 



