118 
House & Garden 
A Small Mark 
with a 
Big Significance 
T o build a modern borne and 
then furnish it with old-fash¬ 
ioned equipment is a false economy. 
A truly modern bathroom is a per¬ 
petual delight, but because to the 
casual eye plumbing fixtures look 
so much alike, only those who buy 
by the trade-mark of the maker may 
know exactly what they are getting. 
TEPECO 
Stands for Excellence 
The reputation of The Trenton Pot¬ 
teries Company’s ware for excellence in 
mechanical construction, quality and design 
entitles these products to first consideration. 
The cost of installation is no greater be¬ 
cause of that quality; the plumbing main¬ 
tenance is less. For evenly glazed vitrified 
china and porcelain is immune to corrosion. 
Sediment will not readily adhere to its 
glossy, self-cleansing surface, and under 
ordinary conditions and normal care it will 
not discolor with years of use. 
Because of our inability to meet the 
demand for all types of TEPECO All-Clay 
Plumbing Fixtures, you may not be able to 
secure the exact style of toilet or lavatory 
that may be specified. The virtue of 
TEPECO ware is such that it will pay you 
to change to a type available rather than 
forego the advantages of TEPECO products. 
Let the star and circle trade-mark be your 
guide. 
Send for our instructive booklet, 
“Bathrooms of Character” 
THE TRENTON POTTERIES CO 
Trenton, New Jersey, U. S. A. 
Boston New York San Francisco 
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ON HOUSE & GARDEN’S BOOK SHELF 
(Continued front page 116) 
From the 7th to the 9th Century 
Chinese ceramic wares found their way 
into the Near East. "From A. D. 833 
to 838, the city of Samarra was the 
home of the Caliphate, and here have 
been unearthed abundant evidence of 
this fact. However, the Sassanian lusters 
were essential Mohammedan as the 
Chinese were unacquainted with this 
technique. 
Harun al Raschid made the City of 
Raqqa his capital when Bagdad became 
unsafe for the Caliphate, but Dr. 
Riefstahl points out that the old poeti¬ 
cal attribution of the Raqqa wares to 
that Caliph’s reign (A. D. 786—809) 
must be given up in view of the fact 
that all the Raqqa so-called were 
excavated from quarters of the old city 
that were not constructed until the 11th, 
the 12th and the 13th Century. 
In the second half of the 7th Century 
the Mohammedan conquerors were 
firmly established on the ruins of the 
preceding Sassanian Empire. Buchara 
and Samarcand were occupied in 674 
and 676. The early years of the 8th 
Century found the Caliphate firmly 
established in Transoxonia. In politics, 
literature, art and science the Arabic 
influence swept over Persia and Turk¬ 
estan. But before long Turkish control 
asserted itself and the power of the 
Caliph of Bagdad dwindled to the con¬ 
fines of his rose garden. With the con¬ 
sequent decrease in Arabian influence, 
the old Persian traditions in literature 
and art were revived, marking the gold¬ 
en age for Persian literature. 
The 12th and 13th Century potters 
in Persia invented a new technique, 
that of overglaze painting, which 
greatly increased, as Dr. Riefstahl tells 
us, the possibilities of polychrome dec¬ 
oration and of elaborate design. This 
brought the beautiful Rhages potteries 
into being, reflecting, so many of them, 
the contemporary styles of miniature 
painting in Persia. Dr. Riefstahl has 
much of especial interest to say on this 
subject. 
The sultanabad wares close the his¬ 
tory of the Classic period in Persia, 
and Dr. Riefstahl tells us that nothing 
new is created in Persia during the 
ISth Century, the most interesting pot¬ 
teries coming from Turkestan, Buchara 
and Samarcand. Chinese influence was 
again felt in the 16th Century and 
called forth new efforts, but these did 
not, like the early Mohammedan wares, 
become a source of inspiration for 
Europe, and these 16th Century Per¬ 
sian wares have therefore only a local 
interest. 
Other sections of Dr. Riefstahl’s 
volume are taken up with ‘‘Pictorial 
Representations on Rhages Pottery”, 
“The Story of Bahram Gur”, the ad¬ 
venturous hunter king (A. D. 420- 
438), one of the most picturesque fig¬ 
ures in Persian history, legend and lit¬ 
erature, (whose exploits were celebrated 
by Firdusi, Nizami, and other Persian 
poets), and “Textile Patterns on Mo¬ 
hammedan Potteries”. The detailed 
descriptions of each of the plates, the 
Bibliography and the Survey of Dates 
Referred to are all that could be de¬ 
sired, and the Index is especially to be 
commended. In passing one wishes to 
congratulate the publisher for having 
produced so valuable a work in so 
harmonious a form. 
Gardner Teall 
T he Physiology of the Ascent 
OF Sap. By Sir Jag.adis Chunder 
Bose, Director of the Bose Research 
Institute, Calcutta. Longmans 
Green & Company. 
The manner in which the sap ascends 
the stems of plants has long been a 
puzzle to botanists and may long con¬ 
tinue to be so, though its solution has 
been attempted by many brilliant minds. 
The difficulties that surround the in¬ 
vestigations of the subject are in some 
cases almost insurmountable. The 
problem is not merely that of how the 
plant secures sufficient moisture for its 
vital processes, but the greater one of 
how it is able to provide and move 
that great transpiration stream which, 
entering at the roots, is lifted upward 
in the stem for many feet and finally 
is evaporated from the leaves. It is, 
of course, known that all plants trans- ! 
pire many pounds of water for each 
pound of dry weight produced—in the 
alfalfa, for instance, more than a thou¬ 
sand pounds are required—but the exact 
method by which the sap is able to 
ascend so rapidly is still more or less of 
a mystery. 
Early investigators of the ascent of 
sap ascribed the phenomena concerned 
to the vital processes of the plant, thus 
taking the problem from the physicist 
as not capable of being investigated by 
any means at his command. Gradually, 
however, the majority of students have 
reached the conclusion that when the 
purely physical processes of capillarity, 
osmosis and evaporation are thoroughly 
understood, their combined action will | 
provide an adequate explanation for the 
phenomena involved. Dixon in 1914 
prov'ed to his own satisfaction, at least, 
that the evaporation from the leaves, 
coupled with a little-understood but 
powerful cohesion of water in the 
transporting tissues was sufficient to ac¬ 
count for the rise of water in any plant. 
To such ideas the author of the pres¬ 
ent volume, who is widely known for 
his experiments on the irritability of 
plants, does not subscribe. He goes 
back to vitalistic causes for his explana¬ 
tion and asserts that the ascent of sap 
is a psychological process which is ! 
maintained by co-ordinated cellular ac¬ 
tivity throughout the plant. He speaks 
of nerves of the plants and insists upon 
the physiological continuity of the plant 
mechanism. By a series of searching : 
experiments he has studied the effects 
of anaesthetics, poisons, varying tem¬ 
peratures, drought, and other stimuli 
on the movement of sap and concludes 
that the rate at which it travels in plant 
tissues is much too rapid to be accounted 
for by osmosis. He assumes, therefore, 
a sort of pumping action or ‘‘pulsating 
activity” in the cells to explain the ac¬ 
celeration observed. By means of an 
electric probe he claims to have located 
these pulsating cells, in the dicoty¬ 
ledons, at the point where wood and 
bark join, that is, in the cortex, and 
has measured their pulsations with a 
sensitive galvanometer. 
It is possible, however, to interpret 
some of the responses observed in more 
than one way. When a drooping leaf, 
ten inches high on a stem, becomes 
erect after the stem has stood in water 
for a time, he assumes that the water 
has travelled upward ten inches, but it 
is quite as likely that the intake of 
water has replenished the lower cells 
in the stem and that the effect, rather 
than the water, has travelled to the cells 
of the leaf. When a pipe a mile long 
is full, or nearly full, of water, a smalt 
addition of water at one end will cause 
a flow from the other, without the ad¬ 
dition travelling the whole length of the 
pipe. As to the statement that the 
water moves through the stem much 
more rapidly than it could by osmosis, 
it may be said that all the water gets 
into the plant in the first place by os¬ 
mosis through the root hairs; in fact, so 
rapidly do these structures absorb water 
that a considerable pressure, known as 
root-pressure, is soon set up in the stem 
(Continued on page 120) 
