418 



SCIENCE. 



[Vol. VII , No. 170 



ducing only a transient effect. 4. Probably the 

 chief cause of a comparative greater destruction 

 can be found in the difference in soil, and more 

 especially in the climate ; that is, when European 

 countries are compared with districts, like California, 

 cultivating a similar variety of vine. It has been a 

 notable feature in California experience that the 

 spread is usually very slow, and only showing notice- 

 able rapidity in exceptional cases. In our observa- 

 tions (see ' Report of college of agriculture, 1886 ') we 

 have shown that a peculiar growth of roots, induced 

 by late rains, or again by surface manuring, will pro- 

 duce the winged form in great abundance. But the 

 general climate of California is extremely dry during 

 this growing period, and therefore no such roots are 

 apt to be formed ; while in the portions of Europe 

 where the spread has been most rapid, their type of 

 vine being similar to that of our own, a growth of 

 fine surface rootlets is undoubtedly induced by the 

 summer rains, and myriads of the winged-form in- 

 sects developed and spread to adjoining vineyards. 

 The effect of fertilizing on the production of simi- 

 lar rootlets is doubtless greater than is usually sup- 

 posed. 



4. Is there any reason to suppose that the pest 

 will be mitigated" by natural causes as time goes on ? 

 As yet there seems to be no evidence in favor of 

 such a supposition. This case should be analogous 

 to that of other insect pests, which have been over- 

 come only by insect enemies. This insect has been 

 with us many years ; and yet no enemy which can 

 destroy all the forms has appeared, although the 

 gall-type, accessible above ground, has undoubtedly 

 been decreased in numbers by such enemies as the 

 thrips, tyroglyphus, and others. No enemy with the 

 needed multiplicity of forms, enabling it to traverse 

 the vine and at the same time all parts of the roots, 

 is known. Until such does appear, there is little 

 doubt that the loss caused by any local disturbance 

 will soon be replaced by the other types, and thus 

 the species will be continued. F. VV. Morse. 



Berkeley, Cal., April 22. 



Topographical models or relief-maps. 



I hope you will find space in your paper for the 

 following description of a new method of making 

 topographical models from contour maps. I com- 

 pleced it a few weeks ago, and have made several 

 models of complicated surfaces. 



Make a careful tracing of the contour lines on 

 waxed or oiled tracing-paper. Linen must not be 

 used, as it will distort the lines when wetted. Paste 

 the tracing on a clear piece of white holly veneer an 

 eighth of an inch in thickness, and cut or have cut, 

 with a fine fret-saw. the lines of contour, leaving 

 spaces now and then, should the lines so run that the 

 intervening wood would drop out. Fasten the veneer 

 to a board, being sure that the surface is flat. Fasten 

 veneer by the edges, and not through the spaces be- 

 tween contour lines. Cut or have cut strips of thin 

 brass, each strip being as wide as the height of each 

 contour line, and insert the strip into the correspond- 

 ing saw-cut in the veneer. They must be pressed 

 down until they touch the board below the veneer. 

 When all the contours are in place, paint the whole 

 surface over with heated wax. which will prevent 

 the moisture of the clay from distorting the wood. 

 When all is coated, fill in the spaces between the 

 strips with clay until only the edges of the brass 



show. Where spaces are left, the strips are cut with 

 a slanting end long enough to span the space uncut, 

 and the line of contour is thus unbroken. 



By this method nothing is left to the eye, and 

 perfect accuracy is gained. I have made some 

 models for Prof. N. S. Shaler, and it was at bis 

 request that I send this description to your paper. 



Henry Brooks. 



Boston, April 26. 



Poison rings. 



Appreciating your kindness in inserting my pre- 

 vious letter, containing a number of questions as to 

 what we know of the past of the pest phylloxera, 

 and what we may expect for its future, answers to 

 which would certainly interest many laymen like 

 myself, and not discouraged by the lack of response 

 from your readers, I venture to send you this. 



In the recently published volume (xx.) of the ' En- 

 cyclopaedia Britannica,' under the head of ' Ring,' 

 it is stated that u Pliny records, that, after Crassus 

 had stolen the gold treasure from under the throne 

 of Capitoline Jupiter, the guardian of the shrine, to 

 escape torture, broke the gem of his ring in his 

 mouth, and died immediately." Hannibal is also 

 recorded as having killed himself with his ring ; and 

 the writer further says, the " anello della morte, sup- 

 posed to be a Venetian invention, was actually used 

 as an easy method of murder." 



Can any of your readers inform me whether any 

 of these ancient rings are still in existence, and, if 

 they are, how they are made, and with what poison 

 they were filled ? A. M. D. 



New York, May 3. 



[We publish this week a reply to ' A. M. D.'s ' 

 queries about phylloxera ; and, doubtless, information 

 as to ' poison rings ' will be forthcoming. — Ed.] 



A swindler abroad again. 



It has just come to my knowledge that the ' tramp ' 

 geologist who has been ' wandering up and down the 

 earth ' for the last three years, the man of many ac- 

 complishments and aliases, is now in the vicinity of 

 St. Cloud, Minn., posing as * Capt.' I. C. White of 

 the West Virginia university. 



I would say, in my own defence, that the title of 

 ' captain ' is not worn by me, and that in this case I 

 can establish an alibi, with the help of my friends. 



Cannot something be done to throttle this nuisance 

 before he scandalizes every geologist in the country I 

 Probably a committee from those whom he has 

 swindled and misrepresented would hunt him down 

 most successfully, and I am sure such a committee- 

 could be trusted to squelch him effectually. 



I. C . White. 



West Virginia university, April 29. 



Pompous prolixity of the French. 



One reads with amused surprise, on p. 403 of the 

 last issue of Science, that the literary style of French 

 scientific writers is characterized by ' pompous pro- 

 lixity.' We all understand that " that which is not 

 clear is not good French." We had supposed that 

 the genius of that sententious language was as much 

 opposed to pomposity and prolixity as to obscurity. 



