July 21, 1905.] 



SCIENCE. 



91 



likely to start on a brief journey, going only 

 about two inches from the edge of his scar, 

 and returning to settle upon it again, some- 

 times within fifteen minutes from the time 

 of his leaving it. In no experiment did I 

 find a Fissurella homing if he had been re- 

 moved more than three inches, though one 

 which had been removed six and a half inches 

 was nearly half way back in twenty-four 

 hours. My departure from Bermuda pre- 

 vented my learning his final fate. Fissurella, 

 like Siphonaria, recognizes his scar and ori- 

 ents himself properly with reference to it as 

 soon as he reaches it. In one instance I 

 found a scar occupied by two animals; one 

 was the owner, who had evidently returned 

 from his wanderings to find that a usurper 

 had already taken possession of half of his 

 home. He had, however, crawled on to as 

 much of the scar as was still unoccupied and 

 the next day was in sole possession, while the 

 intruder had disappeared. Fissurella harha- 

 densiSj then, undertakes short voluntary ex- 

 cursions and returns to his scar, but his power 

 of homing when removed by some one else has 

 not been fully tested. M. A. Willcox. 



MACHINE-MADE LINE DRAWINGS FOR THE ILLUS- 

 TRATION OF SCIENTIFIC PAPERS. 



It is safe to say that the majority of per- 

 sons who from time to time publish scientific 

 papers are seriously hampered in the prepara- 

 tion of text illustrations by the difficulty and 

 expense entailed in the tedious drawing of 

 map, section or diagram. Comparatively few 

 authors can command the services of skilled 

 draughtsmen or have themselves the requisite 

 training to produce satisfactory line drawings. 

 Yet the desirability of greatly increasing the 

 proportion of such illustration in the thou- 

 sands of scientific articles published each year 

 is manifest. That clearness, precision and 

 conciseness in the exposition of a theme are 

 generally enhanced by the use of abundant, 

 appropriate diagrams is as evident as that the 

 blackboard is the constant friend of the 

 teacher of any branch of natural history or 

 philosophy; the printed page needs its black- 

 board. 



Ideally, the author should himself be able 

 to make the original drawing quickly, neatly 

 and artistically. The usual execution of 

 drawing with the pen is, to the average author, 

 discouragingly slow and expensive, not always 

 neat, and still less often artistic. The fol- 

 lowing note relates to some experiments made 

 to increase rapidity and neatness in the pro- 

 duction of line drawings by the use of a ma- 

 chine. At the outset the experiments were, 



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Triangulation stations etc a A a O f h 

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for obvious reasons, planned without any idea 

 of rivaling the artistic work of the pen in a 

 skilled hand. The aim has been to secure 

 economy of time in execution and clear-cut 

 precision of legend for the drawing. In both 

 these respects enough success has been at- 

 tained to warrant the recommendation of the 

 machine method to geologists, geographers 

 and others who desire to prepare useful text 



