8. "On the Projection of the Spectra of the Metals" (American Journal of Science for September, 1865).
9. "On the Construction of a Spectroscope with a Number of Prisms by which the Angle of Minimum Deviation for any Pay may be accurately measured" (American Journal of Science for November, 1865).
10. "On the Heat of Friction" ("Proceedings of the American Academy," 1865).
11. "On the Aqueous Lines of the Solar Spectrum" ("Proceedings of the American Academy," 1866).
By comparing observations with the spectroscope and the hygrometer, it was in this paper first shown that a large part of the air-lines in the solar spectrum are due to aqueous vapor.
12. "On Danalite, a New Mineral Species from the Granite of Rockport, Massachusetts" (American Journal of Science for July, 1866).
This is a well-marked species allied to Helvin, but containing zinc in place of manganese.
13. "On Cryophyllite, a New Mineral Species of the Mica Family, with Some Associated Minerals in the Granite of Rockport, Massachusetts" (American Journal of Science for March, 1867).
Besides establishing a new species, this paper shows that in the veins of the Rockport granite there are closely associated a unicilicate and a bisilicate mica, which are isomorphous with each other, a circumstance which renders probable the theory that the wide variations in the composition of the micas may result from an isomorphous mixture of two similar types.
14. "On Certain Lecture Experiments, and on a New Form of Endiometer" (American Journal of Science for September, 1867).
15. "A Method of determining the Amounts of Protoxide of Iron in Silicates not soluble in the Ordinary Mineral Acids" (American Journal of Science for November, 1867).
16. "Crystallographic Determination of Some American Chlorites" (American Journal of Science for September, 1867).
The paper gives some new measurements of angles, and shows that there are two crystallographic types of chlorites corresponding to the well-known types of micas. It is further shown that there is a variation of optical angles in the chlorites, even on the same specimens, like that observed with the micas, and the inference is drawn that the variation is due to a similar cause.
17. "Atomic Ratios" (American Journal of Science for May, 1869).
It was for the first time pointed out in this paper that what mineralogists have long called the oxygen ratio of a silicate is really the ratio between the atomicities of the acid and basic radicals in these salts.
18. "The Vermiculites—their Crystallographic and Chemical Relations to the Micas, together with a Discussion of the Cause of the Variation of the Optical Angle in these Minerals" ("Proceedings of the American Academy," 1873).
This monograph contains the chemical analyses and crystallographic descrip-
