224 
RERAMIC STUDIO 
STUDIO NOTES 
Mrs. Anna Armstrong Green, wife of Thomas S. Green, 
M. D., and only daughter of Rev. and Mrs. F. C. Armstrong, 
died at the home of her parents, 743 Harrison Street, Chicago, 
Friday night, January 6th. 
Mrs. Green was a member of the "Chicago Ceramic Art 
Association" and the National League of Mineral Painters. 
She was well known in the art world where her original line 
of work and exquisite creations won for her a high place. 
The strength and beauty of her compositions were the result 
of careful, painstaking, thoughtful study, combined with 
a refined and keenly artistic temperament. 
Personally Anna Armstrong Green was a most lovable 
woman, gentle, conscientious, and thoroughly womanly, and, 
I but voice the sentiment of the entire colony of Chicago artists 
when I say, that not only as an artist, but as a dearly beloved 
comrade and friend, will she be missed from our circle. 
Minnie C. Childs, 
2nd Vice-Pres. Chicago Ceramic Art Assn. 
Mr. Cobden of Philadelphia sent us as a Christmas greeting' 
a dainty reproduction in color of his roses, about three by four 
inches in size. 
HOW TO TELL AGE OF POTTERY WITH A MAGNET 
THE attempt to ascertain the age of a porcelain vase b}^ 
testing it with a magnet may appear ridiculous, but a 
French scientist claims, with much plausibility, that he can fix 
approximately the dates of all potteries in this way. 
The magnetic needle does not, as many people suppose, 
point exactly to the north, but deviates from a north and south 
line to an extent which differs in different places, and also varies 
from year to year at the same place. 
At Paris, for example, this deviation, or "declination,'' as 
it is technically called, was \i\ degrees to the east in the year 
1580. In 1663 there was no declination — that is, the needle 
pointed due north. Since then the declination has been wester- 
ly. The greatest westerly declination — about 22\ degrees — 
occurred in 1835, since which time the needle has been slowly 
coming back to the meridian. The declination is now less than 
15 degrees, and in another century it will be zero. 
Furthermore, a freely suspended magnetic needle does not 
He horizontally, but dips toward the north, and this dipping or 
"inclination" varies, as the declination does. It is evident 
that if we know the inclination and declination for all past times 
or know the laws of their variations, so that we can compute 
their values at any epoch, we can fix the date of any occurrence 
by the declination and inclination at that time. 
Now most clay contains iron and is magnetized in the di- 
rection of the prevailing magnetic force — that is, parallel to the 
compass needle. When the clay is "fired," or baked, the di- 
rection of this magnetism becomes fixed, parallel with the di- 
rection of the compass needle at that instant. Hence, if the 
resulting vase or brick were undisturbed, it would preserve, 
graven in it, so to speak, a record of the date at which it was 
made. 
Vases are disturbed, and we cannot tell which side was north 
in the firing kiln, so that we cannot use the magnetic " decHn- 
ation," but we can make use of the dip, or " inclination." 
This ingenious method has been applied to vases of the 
Roman and Etruscan periods. The former gives a very differ- 
ent inclination from the latter, indicating a great difference in 
age, which is at least interesting and gratifying as a first result. 
MULLEN 
Russell Goodwin 
THE muUen stalk is exceedingly decorative, the flower head 
a soft yellow, the leaves and stalk a light grey green. 
When old, the flower head is more of a mahogany shade and 
would be effective against a greyed peacock blue sky, softening 
into mahogany yellow brown and olive green. 
