RUKAL ENGINEERING. 919 



drag are urged as a solution of the problem for earth roads. The animal cost 

 of maintenance does no1 exceed $3 per mile. Culverts ami short bridges of 

 reinforced concrete arc advised. 



Although a general lack of road metal over the State is admitted, the com- 

 mission states that "we believe the earth road is uol a permanent solution 

 of our road problem, so far as the main traveled roads are concerned. In 

 every county the network of main traveled roads should in the end be made 

 permanent hard roads, surfaced with broken stone, if possible, and at leasl 

 with gravel." Bu1 it adds: "We do not advise the construction of roads 

 which cost $5,000 to $10,000 per mile to build, and $100 per mile per year to 

 maintain, unless for a very few very importanl roads. \\'e advise, rather, 

 the construction of such stone roads as can he built in this State and others 

 a1 cods of $1,200 to $2,500 per mile, and of gravel roads such as are being buill 

 in this state for $400 to $600 per mile where the gravel is found aear at hand." 



The use of cement for farm purposes, S. M. Woodwabd I Municipal Engin., 30 

 (1906), \>>. 2, i>i>. 99 102).- The possible scope of concrete as a material for 

 farm buildings, floors, approaches, feme posts, troughs, and other farm purposes 

 is briefly outlined, and its uses in California for irrigation structures are 

 described at more length. Cost data for ditch and reservoir linings and for 

 cement pipe in small sizes are given. 



Denaturized alcohol for farm purposes, ( '. J. Zintheo (Gd8 Engine, 8 (1906), 

 No. J. ;>/>. 6-9). — A review of the possibilities in the use of alcohol made from 

 waste farm products for heat, light, and power, showing the urgent necessity of 

 free alcohol for industrial purposes. 



Any farm product containing large percentages of starch or sugar, such as 

 grains, potatoes, beets, and cornstalks, may be used. Distillers claim that corn 

 at 4<» cents will produce 94 per cent alcohol at 13.5 cents a gallon, and that it 

 has been made at a cost as low as 8 cents. It has been sold for 18 cents a gallon 

 over the tax. While its heating power is about half that of gasoline, its com- 

 bustion is so much more perfect that it is about as efficient, gallon for gallon. 



European governments have all removed the tax on denaturized alcohol, and 

 large areas are devoted to crops for producing it. In America free alcohol 

 would not only insure cheap power, hut would steady the price of corn, and 

 absorb local overproduction of other crops. 



Straw as a substitute for coal, C. Voitelueb (Jour. Agr. Prut., n. ser., tO 

 (1905), Vo. 48, pp. 686-688). — The caloric value of straw is less than one-fourth 

 that of coal, and this fact, added to the difficulty of tiring with straw, makes it 

 a poor fuel for steam boilers. The writer states, however, that when made into 

 producer gas and used in a gas engine, 1 kg. of straw will yield as much power 

 as I! or 4 kg. of coal used to produce steam. Compared with coal at 40 francs 

 per ton. the power value of straw on this hasis would he 150 francs per ton. or 

 something like S.T0 per acre for an average yield. The straw should he baled, 

 and for the sake of economy power plaids should he concentrated in T<» to 100 

 horsepower units. 



The capacity of wind motors, M. RlNGELMANN (Co//////. Rend. Acad. Set. 

 [Port'8], /// t 1905), No. is, /,/,. 688, 689). — The experiments recorded were made 

 on a 12-ft mill with wooden vanes, and hear out former tests in showing that 

 with a constant load the rate of work varies as the first power of the wind 

 velocity. An analytical explanation of the reduced efficiency at higher velocities 

 is offered, which shows that the effective area presented to the wind tends to 

 diminish as the ratio of wheel rate to wind velocity increases. The method of 

 determining the most effective load for a particular locality from daily wind 

 records is given. 



