January 6, 1893.] 



SCIENCE. 



1 1 



It is a little singular that certain species do not vary, species 

 which are not only found from ocean to ocean in North America, 

 but which are nearly or quite cosmopolitan. Why this should be 

 true of some species and not of others is still an open question. 

 If the scorching sun of the desert regions will bleach out one 

 species why will it not do the same for another? The plea of 

 adaptation of coloration for protection cannot be urged htre. 



Not only are colors affected, but size as well, by geographical 

 position. This is probably more marked north and south than east 

 and west. And yet the -variation in size alone is not sutficient 

 for a subspecific division. It is not at all strange that those indi- 

 viduals of a migratory species which push farthest north should 

 possess stronger bones and muscles, and so be larger than those 

 which were not able to fly so far. It would seem natural that the 

 constant recurrence of such a difference would tend, in time, to 

 form a race peculiar enough to he recognized as a sub species. But 

 it has not proven true thus far in the history of the world, and 

 why should there be any change under the same conditions? 



Lynds Jones. 



OberliD, Ohio, Deo. 26. 



On the Use of the Compound Eyes of Insects. 



In an interesting note on the above subject by Mr. E. T. Lewis 

 in Science of Dec. 2, there is a reference to my note on Professor 

 Exner's beautiful researches on the question of how the compound 

 eyes of insects see, in ray recent edition of " The Microscope and 

 Its Revelations." Mr. Lewis says (p. 315), "but it may be as 

 well to note that the figure on page 908 of 'The Microscope and 

 Its Revelations' appears to have been laterally inverted by the 

 engraver," his observations enabling him to say "that in the 

 original photograph the letter R was not reversed as shown in 

 the wood-cut, and the church faced the other nay." 



This is entirely fallacious; the wood-cut in the current edition 

 of the " Revelations of the Microscope " is in every sense correct. 

 It has been seen by Exner. and was copied from the original pho- 

 tograph, which now lies before me as sent me by Professor Exner 

 himself; and a study of " Die Physiologie der Facettirten Augen 

 von Krebsen und Ins^cten " will make this clear. 



W. H. DOLLINGER. 



Lee, LoDdou, S.E., Eugland. 



great problem which has long puzzled Mexicanist students in 

 general. Guided by a luuimous passage occurring in an unpub- 

 lished Hispano- Mexican MS which she had previously discovered 

 in a Florentine library and intends to reproduce in facsimile, 

 Mrs Nuttall may be said to have furnished the key to the hitherto 

 unknown calendar system of the ancient Aztecs. It now seems 

 to be of a very simple and harmonious character and to have been 

 employed by ihem. judging from astronomical calculations, for a 

 period of at least 4,000 \ears. 



The Mexican cycle, it appears from these researches, was one of 

 13,515 days. It comprised 52 ritual years, less five days at the 

 end of the cycle, each year of 260 days, or 51 lunar years of 265 

 days, based on nine moons in each year, or 37 solar years of 365 

 days in each year. At the end of the fifty-first lunar year ten 

 intercalated days made the lunar year equal to the solar year, in 

 such a manner that the new cycle began in the same lunar and 

 solar positions as the preceding cj cle of 18,515 days. Each period 

 began with a day bearing one of four names, acatl, tecpatl, calle', 

 or tochtle'. 



This is the most important discovery hitherto made known by 

 the indefatigable Nahuatl scholar. Full details will eventually 

 be published in one of the Peabody Museum papers of the Ameri- 

 can Museum of Archseolosy, on which Mrs. Zelia Nuttall, special 

 assistant in Mexican archaeology, and director of the same depart- 

 ment in the Columbian Exhibition, has already reflected much 

 honor. A ONES Ceane. 



Brighton, Englaod, Dec. 20, 1893. 



Discovery of Mexican Feather-Work in Madrid. 



There are not many well-preserved specimens of native Mexi- 

 cae feather work in existence, and every addition to their number 

 i-i of interest and importance. During a recent visit to the land 

 which gave birth to the conquerors of Mexico, Mrs. Zelia Nut- 

 tall — w hose researches on Mexican antiquities are well known — 

 was so fortunate as to discover a fine example of Mexican feather- 

 mosaic in the shape of a valuable shield, with an authentic history, 

 preserved in the Royal Armory of Madrid. It is known as the 

 shield of Philip the Second, for whom it was indubitably made 

 in Spain of cane and leather in the oval shajje of the Moorish 

 adarga. It was then sent out to Mexico with four beautiful 

 Spanish designs of historical scenes and a central device. These 

 were executed in Mexico entirely of feather-mosaic, which covers 

 the whole surface of the shield and makes it one of the most sur- 

 prising and superb examples of this curious lost art of miniature 

 painting with feathers. Mrs. Nuttall has paid considerable atten- 

 tion to the subject of ancient Mexican feather-work, and has 

 already accumulated novel data which promise to throw light on 

 the methods of its manufacture. We may look for an interesting 

 paper on this subject from her pen before long. 



Soon after the shield in question was identified by her as of 

 Mexican workmanship — an uni-ecognized fact which was not re- 

 corded in the oldest Inventories — it was removed from the Royal 

 Armory and placed on exhibition in the interesting Hispano- 

 American Historical Exposition in Madrid. In the Spanish section 

 of the same building may now be found also the elaborate tables, 

 fourteen metres long, originally dasigned to illustrate Mrs. Nut- 

 tail's "Preliminary Note on the Ancient Calendar of the Axtecs," 

 which formed the most original and valuable communication 

 presented to the recent Americanist Congress at Huelva. It was 

 then generally admitted that Mrs. Nuttall had fairly solved the 



Is it Instinct or Intelligence ? 



I HAVE a nearly pure-blooded water spaniel. Though a great 

 pet and most valuable watch-dog, in my busy life I have devoted 

 little time to training him, — rather have watched carefully the 

 development and application of his own powers, under a uni- 

 formly kind treatment. When only five weeks old, he made his 

 first debut into the open world, — following m ither and myself 

 to church. Crossing the street, we heard the patter of little feet, 

 and, looking around, I saw his nose close to the ground as the lit- 

 tle ball trudged along. I took him home and started again, only 

 to have the performance repeated, but this time I shut him in 

 the house. Just as church service opened, mother thought she 

 felt something strangely warm at her feet. And lo I there was 

 Master Carlo. He had escaped, perseveriugly followed our track 

 around two bloik-i. and discovered mother in the congregation. 

 From that time a remarkably keen scent has been a prominent 

 quality Esrly he manifested a love for watching and chasing 

 chickens, — a pastime not to tie neglected with the small opportu- 

 nities of the city. We soon by kindntss and firmness and much 

 talking, broke him of di^^turbing our own chickens. We often 

 took a little chick m our hands, and said to him '■ pretty chickey, 

 Carlo's chickey I " and hI oweii hi a to lick it gently. Soon it 

 was not only safe, but safer to have him in the pen with the 

 chicks i\nn othpr>vise, as then no rat or mouse dared venture 

 there. From the Hr-t, ' arlo has deemed these marauders worthy 

 of death whenevpr and wherever sefn, and acts out his convic- 

 tions. .\slhe chii-kens grew, and Thanksgiving approached, their 

 number wa> redu'-ed to tweUe, and these were transferred to 

 the barn. Every nis'lit 'or two years Carlo made a detour of the 

 perches, giving e ch fo>vl a i^ood lick, — they were so acquainted 

 it did not alarm them at il, — anil if one or more of the number 

 was absent, he wo iM ir im-rliately scour the premises till it was 

 found then gav^ a |i cu .ir ba' k indicating the discovery ; nor 

 would he ive it up tii he number was complete. Could he 

 count? How did he now there should be just twelve — no 

 more, no less? Oi'casionally a stray fowl would come to our 

 yard. Thi-; he 'or .i ued by keeping it constantly "on the 

 move." not b' miiii i^ < un. but simply kept it walking about, 

 persistenth mdi^-s i i "it) the street, when he considered it 

 game ami piirs.ie 1 it uriUuhly. The following spring and 

 summer, us ihi- chic ga i tn lay, he took it upon himself, 



without any tHdi- . to find and bring in the eggs, never 



sucking ari> , :i 1 1 :\ mg ihem if broken, it was because 



he laid th.'in l > ily upon the veranda floor. When a 



