PROCEEDINGS OF SECTION H. 657 



Tar is also applied to roads, being broomed over the surface, wMcli 

 is sprinkled witb sand or gravel before it dries. There can be no doubt 

 that where the traffic is light this dressing produces a very satisfactory 

 and cheap treatment, and is entirely successful in reducing dust and 

 noise and in pleasantness of travel ; but it is extremely hot, and if 

 double-distilled tar is used noise is not reduced very much, and the 

 clatter of horses' hoofs becomes very marked in narrow streets. The 

 cost varies greatly with the price of tar. In Adelaide tar costs 6d. 

 per gallon at the site, and one dressing costs from Ifd. to 3d. per square 

 yard, according to the amount of repairs to be effected, and it is rarely 

 less than 2d. On roads with a fairly heavy amount of traffic this coat- 

 ing in winter frequently works up into a black mud, M'hich is very 

 objectionable. Although it is serviceable on many roads, the limited 

 supply of tar and increasing demand point in the direction of much 

 higher prices. Yet, where the cost does not exceed the average annual 

 cost of repairs to macadam roads, its use is preferable to other sub- 

 stances which do not provide a wearing surface in themselves. 



There has recently been placed on the market quite a number of 

 patent lines having an oil base, and these, or some of them, seem to 

 offer great promise of success under almost all circumstances of traffic 

 and weather. 



It should, however, be remembered that air-borne dust is not 

 amenable to any local treatment, no matter how effectually it may 

 preserve the surface to which it is applied. 



The following list has been selected as illustrating the importance 

 attached to this subject in England, and in fact Europe and America 

 generally, and are from experiments made in England : — 



Westrumite, a solution of petroleum and water, costs in England 

 £8 10s. per ton, and when used in 10 per cent, solution costs ^d. per 

 square yard per application. In Australia the price quoted is double, 

 representing over Id. per square yard per application. 



Buslroyd, a patent liquid preparation manufactured from tar, 

 has pleasing odor, is not soluble in water and binds road surface. It 

 costs in England £4 per ton, but, having to be used full strength, does 

 not go so far as westrumite, and would probably be as costly. 



Akonia is another patent preparation, and so far seems to occupy 

 a similar position to dustroyd. 



In 1902-3 and 4 Mr. John A. Brodie. M. Inst., C.E., City Engineer 

 of Liverpool, conducted extensive experiments with oil mixtures, and 

 the following brief summary of the results will be of interest : — Experi- 

 ments were made with creosote oil, hot and cold, also mixed with 

 pitch, resin, and tallow ; coal tar hot ; cheap waste petroleum ; west- 

 rumite ; crystallised creosote ; pyneoline ; and calcium chloride. 



The co'st varied from Jd. to ^d. per square yard per coat, the lowest 

 being that of cheap crude oil. Chief objections were raised to the 

 smell of creosote oil, but it banished flies. The surface having the 

 cleanest and whitest appearance was that coated with creosote oil 

 mixed with resin, while that covered with the same oil mixed with 

 tallow had the least odor. The crude Texas petroleum gave the most 

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