exceptions to this rule will be only where steel is to be assembled Mr. Whitehead. and stored for a number of months before erection. With the adoption of this system the only parts painted in the shops would be the surfaces coming in contact in riveted work, bottom of bed plates, bearing plates, and any parts that are not accessible for painting after erection. After the steel has been erected a corps of cleaners provided with hammers, steel scrapers and iron brushes, should precede the painters and properly clean all surfaces. The question of sand-blasting has been thoroughly discussed at various times by parties in interest, and has been practiced to some extent; but, so far as I have been able to learn, it has never been reduced to a scientific or practical basis to the extent that it ceases to be a menace and hindrance to the manufacturers of steel. In fact the information obtained through the interviews which I have had, not only with the superintendents of steel mills and assembling shops, but also with the superintendents of railroad companies and railroad construction companies, who have done sand-blasting in the field, shows that so far as their experience is concerned this method is impracticable and does not really secure the desired results within reasonable cost. It is a question of wearing away the mill-scale by the force of the sand-blast rather than its removal by disruption. The time required is altogether too long, and hence this process is too expensive. Sand-blasting brings up the question of shop output. The majority of the assembling shops are altogether too small for the output desired by their owners and in consequence of this fact the cleaning of the steel, before applying the shop-coat of paint, is sadly neglected. Exceptions to this rule are rare, and where the right methods are adhered to the results are apparent to even a casual observer. Such shops are well-known and esteemed by all of the manufacturers of paints of the higher grades. By the neglect of proper cleaning, the assemblers become the steel's worst enemy. The structural engineer figures the minimum amount of steel to carry the maximum load, using a reasonable factor of safety to overcome any defects of manufacturing. He assumes that all deteriorating elements such as mill-scale, dirt, and rust will be removed before the preservative coating is applied which is intended to maintain the steel in good condition indefi Mr. Whitehead. nitely. If the shop neglects its work by omitting the most essential part, namely: the proper cleaning of the surface of the steel before applying the preservative coating, then that shop becomes a factor of danger of which the engineer has taken no account in his calculations. I believe that I voice the sentiments of all engineers and investors when I caution the assemblers to stop in their rush to dispose of tonnage and to prepare the surface of their product properly before painting, or else this neglect may bring about the use of some other material of construction. This subject is, in fact, under discussion in all quarters, owing largely to the rapid deterioration to which steel is subject, caused primarily by its treatment before passing from the hands of the assembler. REPORT OF COMMITTEE G ON THE MAGNETIC TESTING OF IRON AND STEEL. Your Committee is able to report progress along the several lines of investigation proposed in the report of one year ago. In view of the desire to carry these investigations further than they have now progressed, the Committee has thought it desirable to withhold a statement of the results obtained until the specific experiments now in progress shall have been completed. The Committee would make acknowledgment of the assistance which has been rendered by the various manufacturers of electrical iron and steel, as well as the manufacturers of electrical machinery, who have assisted the Committee by supplying samples for testing and offering valuable suggestions. Respectfully submitted on behalf of the Committee, Chairman. REPORT OF COMMITTEE H ON STANDARD TESTS FOR ROAD MATERIALS. The Committee on Standard Tests for Road Materials respectfully reports the following: The third meeting of the Committee was held in New York, on January 17, 1905. The work of the several sub-committees, was discussed and arrangements made for continuing the different lines of investigation. The fourth meeting of the Committee was held at Atlantic City, June 29, 1905, and the following specifications from the subcommittees on macadam tests and asphalt tests were approved by the Committee and are respectfully recommended to the Society for adoption. SPECIFICATIONS OF TOUGHNESS TEST FOR MACADAM ROCK. In the consideration of macadam road materials, toughness is understood to mean the power possessed by a material to resist fracture by impact. In testing macadam rocks under impact, it has been found best to apply a number of blows of successively increasing energy and note the blow causing failure. The following test involving this principle is, therefore, recommended for determining the toughness of rock for macadam road building. 1. Test pieces may be either cylinders or cubes, 25 mm. in diameter, and 25 mm. in height, perpendicular to the cleavage of the rock. Cylinders are recommended as they are cheaper and more easily made. 2. The testing machine shall consist of an anvil of 50 kgs. weight, and placed on a concrete foundation. The hammer shall be of 2 kgs. weight, and dropped upon an intervening plunger of 1 kg. weight, which rests on the test piece. The lower or bearing surface of this plunger shall be of spherical shape having a radius of 1 cm. This plunger should be made of hardened steel, and pressed firmly upon the test piece by suitable springs. The test piece should be adjusted, so that the center of its upper surface is tangent to the spherical end of the plunger. 3. The test should consist of a 1 cm. fall of the hammer for the first blow, and an increased fall of 1 cm. for each succeeding blow until failure of the test piece occurs. The number of blows necessary to destroy the test piece is used to represent the tough ness.. STANDARD METHOD OF ANALYSIS OF BITUMINOUS PAVING MATERIALS. The method consists in treating a definite quantity of the material under examination with a specified amount of carbon bisulphide at ordinary temperatures, allowing this to stand undisturbed for a sufficient time to permit of a subsidation of the insoluble matter. The solution is then decanted off into another receptacle and the residue again treated with the solvent. After standing a second time for subsidation, the two solutions are filtered through a Gooch crucible, fitted with an asbestos plug. The filtrate is then evaporated down and the residual bitumen burnt off and the weight of the ash added to that of the residues in the receptacle and on the filter. The difference between the weight of the substance taken and the combined weight of the residues, is the bitumen extracted. It is further recommended that this method be applied to the extraction of bituminous paving materials with naphtha. While this method for the examination of bituminous materials has been agreed upon, there yet remains to be described minor details relating to the character and quantity of materials used in making the tests; and it is, therefore, recommended that the specifications for these tests be referred back to the Committee with power to act. Respectfully submitted on behalf of the Committee, A. N. JOHNSON, Chairman. Secretary. |