38 



SCIENCE. 



[Vol. XX. No 493 



ficial puriflcation of tbeir water supplies, but it cannot be 

 said that the conditions necessitating- such action generally 

 exist as yet. In most eases the safer and more economical 

 course will be found to be either the securing- of an unpol- 

 luted water, if such be available, or the protection from pol- 

 lution of existing sources of supply. 



LETTERS TO THE EDITOR. 



#** Correspondents are requested to be as brief as possible. The loriters name 

 is in all cases required as proof of good faith. 



On request in advance^ one hicndred copies of the number containing his 

 communication will be furnished free to any corresiiondent. 



The editor willbe glad to publish any queries consonant with the characftr 

 of the journal. 



American Weeds. 



Phofessor Bteon D. Halsted of the New Jersey Experiment 

 Station has rPL-ently presented to the agricultural public a list of 

 "American Weeds," — mostly phaneroiiaras, — which contains 

 no less than 751 varieties and species, exclusive of noxious fungi. 

 Well may the long-suffering farmer turn up the whites of his 

 eyes at this formidable list. A closer examination, however, 

 shows us among the ■' weeds " all our cultivated clovers, medics, 

 vetches, and many of our best agricultural grasses. The criterion 

 used by the New -Jersey botanist in deciding what to admit and 

 what to exclude from his catalogue is not apparent, and no word 

 of explanation is vo.uchsafed. 



In the vegetable kingdom, if not in the United States Republic, 

 it is true that •' it is self-evident that all plants are born free and 

 equal." The distmguishing of plants as weeds and not weeds is 

 purely human and artificial. The popular idea of a weed seems 

 to be a repulsive, or hurtful, wild plant. But few persons give 

 exactly the same definition. I have been at some trouble to se- 

 cure the definitions of a number of intelligent persons, and give 

 below a few samples: — 



"A plant where .vou don't want it." — Director Experiment 

 Station. 



" A noxious or useless plant " — Curator of Mwseuvi. 



" A plant out of place.'' — Chemist. 



" A troublesome plant." — Chemist. 



"An obnoxious plant of many species not fit for food or medici- 

 nal purposes." — Clerk. 



" A plant not edible, so far as known, nor medicinal, or otlier- 

 ■wise serviceable to man, and which always thrives where not 

 wanted. " — Inspector of Fertilizers. 



"A plant for which we have no use so far as we know.'' — 

 Meteorologist. 



" (1) Underbrush or bushes; (3)auseless or troublesome plant." 

 — Webster. 



My own de6nition : Any plant which from its situation or in- 

 herent properties is hurtful to human interests; a vegetable mal- 

 efactor. 



By the usage of the English language the name " weed '' is 

 connotative and implies in a plant a bad and hurtful quality. 

 Used metaphorically or analogically it is always a term of oppro- 

 brium. 



If we were dealing with individual plants as courts of justice 

 deal with persons, each particular plant might he properly de- 

 scribed as a weed or not weed according to the circumstances of 

 each case. But here we are dealing not with individuals but with 

 species and varieties, and can take note only of the general char- 

 acter of the groups. If we have planted a bed of pansies, and 

 there springs up among the pansies a red clover plant, this particu- 

 lar plant is hurtful to us, and therefore is treated as a weed, but 

 we are not therefore justified in writing the species Trifolium 

 protense in a list of weeds The general character, — the qualities 

 for which the clover genus generally and this species especially 

 are noted, are good and beneficial to mankind. It was only by 

 chance or the carelessness of some one that this clover plant got 

 into our flower-bed. "The plant out of place" definition of a 

 weed can refer only to a particular plant. It cannot be applied 



to a species, for a plant of any species is liable to be occasionally 

 misplaced. 



We must maintain then that the inclusion in a list of weeds of 

 such plants as the clovers, medics, vetches, and agricultural 

 grasses is unjustifiable and wrong. 



A large number of Professor Halsted's "weeds" are mere 

 ' ' wildlings of nature " for which we have as yet found no im- 

 portant use. But justice requires that in the case of plants as 

 well as persons every one shall be held innocent until proven 

 guilty of wrong. 



Both from an sesthetic and from a practical standpoint it is true 

 that most of these so-called weed jjlants are more useful than 

 hurtful. They clothe and beautify waste places. Many of these 

 wild plants furnish food and nectar for honey bees, and all aid 

 more or less in conserving the fertility of the soil, prevent wash- 

 ing etc. It is as unjust to stigmatize such plants as " weeds'' as 

 it would be to call all savage tribes criminals. 



Professor Halsted omits wholly and without comment noxious 

 fungi from his list of weeds. Yet these are our very worst and 

 most dangerous weeds. In number they far outrun all the phan- 

 erogamic species. 



To justify its inclusion in a list of " American weeds " a plant 

 must not only possess a positively noxious character, but must 

 also be sufficiently obnoxious or wide spread to give it a national 

 reputation. 



If we exclude from Professor Halsted's list all obscure and 

 non-noxious species we shall have left about 150 species of weed- 

 plants worthy to be called "American "Weeds." 



Gebald McCaethy. 



N. C. Experiment Station, Jnly 5. 



Some Remarks oa Professor Cyrus Thomas's Brief Study of 

 the Palenque Tablet. 



In Science, No. 488, Professor Cyrus Thomas stated that " the 

 particular manner of reckoning the days of the month " — or more 

 precisely, the exact designation of a date by the sign of the day and 

 the position it holds in the number of twenty days (uinal) that 

 people are in the habit of calling a Maya month — as it is found 

 not only " in some of the series of the Dresden Codex." but through- 

 out the whole of it. is also found on the Palenque tablet. This 

 statement undoubtedly is a correct one. But Professor Thomas, 

 following Professor Forstemann, asserts that the " peculiarity of this 

 method is that the day of the month is counted not from the first 

 of the given month, but from the last of the preceding month ; 

 thus the fifteenth day of Pop, beginning the count with the first, 

 will, according to this method, be numbered 16." If it were really 

 so, this method of reckoning tlie days of the month would be a 

 very curious one, and hardly to be understood. Professor Forste- 

 mann based this assertion on the supposition that the calendar 

 system of the Dresden Codex is the same as that which prevailed 

 in Yucatan at the time of Bishop Landa's writing. In vol. xxiii. 

 of the Zeitschrift fiir Ethnologic, published by the Berlin An- 

 thropological Society, in a paper entitled "Zur mexikanischen 

 Chronologie, mit besonderer Beriicksichtigung des zaposekischen 

 Kalenders," I have shown that the priests who wrote down the 

 Dresden Codex did not begin their years with the days kan, muluc, 

 ix, cauac, as in Landa's time, but with the days been, e'tznab. 

 akbal, lamat, exactly corresponding to the aeatl, tecpatl, call, 

 tocbtl (cane, flint, house, rabbit), the signs used by the Mexicans 

 to designate their respective years. Beginning the years in this 

 manner, the day 4 ahau 8 cumku is really the eighth day of the 

 month cumku in the been, or " cane," years. The day 9 kan 12 

 kayab is really the twelfth day of the month kayab in the same 

 been, or " cane. ' years ; and thus with all the other dates through- 

 out the whole Dresden Codex. 



The evidence derived from the fact that the same method of 

 numbering the days of the month, that is to say, the same method 

 of beginning the years, is also found in the Palenque tablet, leads 

 — I agree with Professor Thomas — to the inference "that there 

 were intimate relations between the people of this city and those 

 where the Dresden Codex was written, and that there is no very 

 great difference in the ages of the two documents." On the other 



