124 



SCIENCE. 



[N. S. Vol. XV. No. 369. 



Some Observations concerning the Navalio 

 Blanket Industry: Prank Russell. 

 The lantern slides not arriving in time, 

 Dr. Russell did not read his paper. He, 

 however, very kindly authorizes the secre- 

 tary to make use of the abstract. Some 

 tendencies in the progress of the Navaho 

 blanket industry are described. The most 

 noticeable changes are in the kind of yarn, 

 the quality of the work and in the designs. 

 Styles vary in different localities so that 

 a little experience will enable one to name 

 the district from which a given specimen 

 comes. Methods of cheating the trader are 

 described and an account given of the imi- 

 tation Navaho blankets now offered for 

 sale. The author tells how to identify imi- 

 tations. 



The Beginnings of Lithoculture : W J Mc- 



Gee. 



Discussion: Fewkes, Thompson, Grimes, 

 McGee, Hudson. 



Certain Forms of ' Winged-perforated ' 

 Slate Objects: Waeben K. Moorehead. 

 Mr. Moorehead 's paper was fully illus- 

 trated by means of numerous originals and 

 drawings. He called attention to the 

 necessity of an archeological nomenclature 

 for the various ' unknown forms ' in slate 

 and granite which have hitherto been 

 called ' ceremonials '■ — a meaningless term 

 in the opinion of the author. The paper 

 is purely descriptive, dealing with form, 

 type, distribution, etc. 



Discussion: Culin, Moorehead. 



A Voice Tonometer: Carl E. Seashore. 



An exact and ready method of determin- 

 ing the pitch of tones in singing is de- 

 scribed. The apparatus is a modified form 

 of that described by Scripture, Yale 

 Studies in Psychology, IV., 135. It Avorks 

 on the principle of the stroboscope and fur- 

 nishes a direct reading of the vibration 



frequency of any tone sung within the 

 range of two octaves. The reading is ac- 

 curate to the twenty-fifth of a tone. Illus- 

 trations of results are given from measure- 

 ments on the manner and the accuracy of 

 striking a tone, singing the scale, singing 

 the chromatic scale, singing an air, the sing- 

 ing of two notes in unison or in parts, and 

 the singing of the least producible differ- 

 ence in pitch. The last named measure- 

 ment is the most important because it fur- 

 nishes a unit for the study of motor pro- 

 cesses in singing and speaking. 



The Psychological Elements of Visual 

 Space Orientation about a Horizontal 

 Axis: Robert MacDougall. 

 The paper is a summary statement of the 

 results of experimental work carried on in 

 the Harvard Psychological Laboratory 

 dui"ing 1900-1901. Its problem is the de- 

 termination of factors— and their values 

 — of resident and transient sensation which 

 enters into the location, by the human sub- 

 ject, of points in the horizontal plane of 

 the eyes. The experimental variations in- 

 volved comprise the characteristics of 

 visual determination inanordinary illumin- 

 ated field, of the location of a luminous 

 point in an otherwise dark field, and of 

 orientation in complete darkness, in the 

 case of both binocular and monocular vi- 

 sion. The points of greater importance 

 here are the characteristic positive or nega- 

 tive errors of displacement in the subjec- 

 tive plane of the horizon, and the range of 

 the normal mean variation; the influence 

 of the cooperation and disjunction of the 

 two eyes in the act of vision ; and the gen- 

 eral function of eye strain in such forms of 

 space orientation. Special conditions of 

 body strain are taken up, and an analysis 

 made of the typical errors introduced into 

 the process of space orientation by inter- 

 ferences with the normal body-relations. 

 Of these artificially induced conditions the 



