March 13, 1903.] 



SCIENCE. 



419 



scribed in the paper, as a contribution to 

 the literature of the subject. 



Portland Cement, Considered as a Solid 

 Solution: Clifford Richardson, Long 

 Island City, N. Y. Read by title. 

 While the literature on the subject of 

 the constitution of Portland cement is very 

 extensive, in reviewing the same the writer 

 has discovered that the conclusions which 

 have been arrived at are neither uniform 

 nor supported by satisfactory evidence of 

 a synthetic nature. He has, therefore, pre- 

 pared in the laboratory all those silicates 

 and silico-aluminates which are supposed, 

 according to the theory of varioiis writers, 

 to occur in Portland cement clinker. The 

 results of a study of these preparations 

 under the microscope, by petrographie 

 methods, and in their relations to water, 

 show that many of the theories heretofore 

 advanced are imsound, and the Portland 

 cement must be considered to be a type of 

 solid solution, as it presents features quite 

 similar to those found in alloys of the 

 metals. 



A Characterization, Classification and No- 

 menclature of Native Bitumens: Clip- 

 ford Richardson, Long Island City, 

 N. T. Read by title. 

 This paper has been written because of 

 the appointment of a committee, by the 

 International Association for Testing Ma- 

 terials, on the subject of the nomenclature 

 of bitumen. 



Many classifications of the native bitu- 

 mens have been attempted in the past, but 

 they have been based upon insufficient data. 

 During the past ten years the writer has 

 had an opportunity to examine a very large 

 number of native bitumens, and to compare 

 them with type specimens, which are now 

 generally imavailable, through the exhaus- 

 tion of the mines. The evidence accumu- 



lated in this way forms the basis of the 

 proposals contained in the paper. 



In the course of the examination gra- 

 hamite, which has hitherto been described 

 as only coming from West Virginia, has 

 been found to occur in an easily recog- 

 nizable form in Colorado, Indian Terri- 

 tory, Cuba, Trinidad and Mexico; alber- 

 tite, in Utah and several other localities; 

 and various types of asphalt in some 200 

 or 300 different localities. 



The evidence thus obtained has been 

 carefully analyzed, and the following 

 classification of the native bitumens de- 

 duced : 



Bitumens : 

 Gas: 

 Natural gas. , i 



Marsh gas. 

 Petroletim,. 

 Paraffine oils. 



Rich in sulphur derivatives. 

 Poor in sulphur derivatives. 

 Cyclic oils. 

 Russian, stable polymethylenes. 

 Calif ornian, asphaltic polymethyl- 

 enes. 

 Mixed oils. 



Containing both paraffine and cyclic 

 hydrocarbons. 

 Maltha. 

 Solid Bitumens: 



Originating in paraffine hydrocarbons. 



Ozocerite, hatehetite, etc. 

 Originating in cyclic hydrocarbons. 



Terpenes, fossil resins, amber, etc. 

 Polymethylenes and their derivatives. 

 Gilsonites. 



Asphalts, including glance pitch. 

 Grahamites ( asphaltites ) . 

 Individual species. 



Manjak. 

 Uvalde County, Texas, bitumen, etc. 

 The grahamites rapidly shade into the 

 pyrobitumens. 



