358 BULLETIN OF THE NEW YORK STATE MUSEUM 



There was no perceptible change in the appearance of the samples after 

 treatment. 



The loss per cent appears in column 17. 



4. Determination of the effect of continued action of sulphurous acid gas 

 upon the wet samples. — The weight of specimens used was about fifty grams 

 each. The treatment in this test was similar in all details to the preceding 

 one, save that sulphurous acid gas was used instead of carbonic acid gas. 

 The exposure in this test was for thirty-one days. 



5. Determination of the effects produced upon the samples by treatment 

 with dilute sulphuric acid. — Small cubes, three-fourths of an inch on a side, 

 were used for this test. The samples were dried in a water bath at 212^ F., 

 to a constant weight. They were then placed upon a perforated support 

 and immersed in dilute sulphuric acid. The acid solution contained one per 

 cent of sulphuric acid, H2SO4, and the volume used at once was two gallons. 

 After an immersion of forty hours the acid was drawn off and replaced by a 

 fresh supply. This remained upon the samples twenty-four hours, when it 

 was run off and a third fresh portion added, which was allowed to remain 

 eight hours. It was then drawn off and a gentle stream of clear water passed 

 through the vessel for some time, until the samples were entirely cleansed 

 from the effects of the solvent action of the acid. They were then carefully 

 removed to the water bath and dried at 212'' F., to a constant weight. 



Weigh! of sample before treatment — Weight of sample after treatment 



Per cent of loss = ■ X 100. 



Weight of sample before treatment 



The comparative effects of this test will be found in column 22 of the 

 table. 



6. Determination of the effects produced by repeated alternate freezing 

 and thawing. — The specimens used for this test weighed from three hundred 

 to four hundred grams. They were saturated with moisture and then placed 

 in a closed vessel, which was surrounded with a freezing mixture of ice and 

 salt. After an exposure of about twelve hours the vessel was opened and the 

 samples found frozen solid. They were removed, carefully examined to dis- 

 cover any flaws or cracks, and at once put into an air-bath at 212° F. This 

 treatment was continued about twelve hours when the samples were removed 

 and at once put in water of a temperature of 40*^ F. After cooling they were 

 again examined for checks or flaws and the preceding treatment was repeated. 

 Seven successive treatments were made the samples being examined after 

 each treatment. Results of this test are in column 23. 



7. Effects produced in the samples by high heat and subsequent rapid 

 cooling.-- Small cubes of the dr}^ samples were used for this test. They were 

 closely packed in the closed muffle of a Hoskins assay furnace, A copper 

 rod was inserted in the opening at the top of the muffle and its lower ex- 

 tremity brought to the center of the mass of cubes, an opening having been 

 left for the purpose. This lower end could be seen from above without 

 removal of the rod. Heat was then applied and the blast gradually increased 

 until an intense heat was produced. The copper rod was closely observed 



