September 17, 1909] 



SCIENCE 



373 



mediate. If hand charts are desirable it is 

 expedient to reserve one chart for each of the 

 great divisions of physics, dynamics, molecu- 

 lar physics, acoustics, heat, light and electric- 

 ity. I attach such a chart of names bearing 

 on the history of dynamics, in which the main 

 coordinates only have been indicated, as the 

 smaller divisions should be in a subordinate 

 color. It shows, for instance, the dearth of 

 interest in such subjects in the middle of the 

 sixteenth century and toward the beginning of 

 the seventeenth century, except on the part of 

 a few men of irrepressible genius, as well as 

 the terrific general onslaught which occurred 

 with the beginning of the nineteenth century. 



To make the chart more useful the chief 

 date in each life should be indicated by a 

 crossline (not shown), as for instance in case 

 of Newton, the date of publication of the 

 " Principia," of the " Optiks," etc. 



I am writing this note with the hope that 

 somebody will undertake the work seriously 

 and with some degree of completeness. It 

 seems to me clear that available wall diagrams 

 of this kind would not only enliven the work 

 of the teacher of a forbiddingly difficult sub- 

 ject, but would suggest the vast array of pro- 

 found investigation to which the physics of the 

 present day owes its assurance and trenchancy. 

 Carl Barus 



Bbown Univebsitt, 

 Pbovidence, E. I. 



SPECIAL ARTICLES 



ON THE OCCURRENCE OF THE LITTORAL BARNACLE 



CHTHAMALUS STELLATUS (POLl) AT 



WOODS HOLE, MASS. 



To one acquainted with the world-wide dis- 

 tribution of this barnacle, it would seem rather 

 superfluous to call attention to its presence in 

 any specific locality. It is a rather curious 

 fact, however, that this abundant and almost 

 cosmopolitan species seems to have hitherto 

 escaped the notice of those who have listed the 

 New England fauna. Neither Gould (" In- 

 vertebrate Animals of Massachusetts," 1840), 

 nor Verrill (" Invertebrate Animals of Vine- 

 yard Sound," 1873), nor Miss Eathbun 

 (" Fauna of New England : List of the 



Crustacea," 1905) have included this barnacle 

 among the New England species, though cer- 

 tain far less common forms are listed by each of 

 these writers; and the only reference of which 

 I am aware to its occurrence on the Atlantic 

 coast of North America is contained in Dar- 

 win's " Monograph of the Cirripedia," in 

 which he refers to " some specimens attached 

 to oysters sent to me by Professor Agassiz, 

 from Charlestown " (p. 457). It would seem 

 more than possible that Charleston is here in- 

 tended, for on a previous page (456), Darwin 

 includes " Southern United States (Charles- 

 town) " among the localities from which 

 Chthamalus stellatus is recorded. I am in- 

 formed by Miss Eathbun that no specimens of 

 this barnacle from New England are known to 

 be contained in the TJ. S. National Museum 

 collections. Through the kindness of the 

 curator, Mr. C. W. Johnson, I have examined 

 specimens of this species (varieties communis 

 and fragilis), contained in the collections of 

 the Boston Society of Natural History. The 

 locality has not been recorded, however, and 

 there is nothing to indicate whether or not the 

 specimens came from New England waters. 



The author was first led to look for this 

 species at Woods Hole during the present 

 summer, when he found it to occur in consid- 

 erable numbers on Penzance Point, along the 

 shore of Woods Hole passage. Further search 

 has revealed its presence on the piles of piers 

 at Woods Hole, New Bedford and Vineyard 

 Haven, and on rocks at Nobska Point, 

 Nonamesset Island, and the shore of Buz- 

 zards Bay near Woods Hole. It is prob- 

 able, indeed, that its local distribution is 

 very general. At the last named point 

 this species seems to be particularly abun- 

 dant. It extends considerably higher up on 

 the boulders than does Balanus halanoides, 

 with which, however, it is associated at a 

 lower level. It thus occurs at points which 

 must be uncovered by the tide for the greater 

 part of the time. In local waters, so far as I 

 have seen, Chthamalus never grows in such 

 dense clusters as does Balanus halanoides, and 

 indeed it appears unable to compete very suc- 

 cessfully with the latter in its proper zone. 



