MaARcH 29, 1901.] 
tive to minutes instead of seconds, now be- 
comes K = 26A Un,e/C. For if the velocity 
of the ions produced by phosphorus is like 
that of other gaseous ions, U is of the order 
(say) of 1 em./sec (Rutherford, Townsend, 
Chattock) and e of the order of 7 x 10~” 
electrostatic units or 2.4 x 10—” coulombs. 
The ratio of areas in my condenser was 
.35, the area A = 132 cm’., the capacity C 
about 90 cm. or 10~™ farads. Finally the 
observed value of Kas used in computing 
the above curve was K= .634. Thus the 
initial saturation n, = .634 x 10~/26 x 
1382 x 1 x 2.4 x 10-"= 8 x 10° nearly. 
Hence if all the ions which reach and are 
absorbed by the condenser plates actually 
convey electric charge, less than », = 10 
ions per cubic centimeter occur in the satu- 
rated emanation contiguous to the surface 
of the phosphorus grid. 
If now, instead of U=1 em./sec. for the 
field of a volt per centimeter, the absorption 
velocity & = .3 cm./sec. found in the absence 
of an electric field (Am. Journ., March), 
were taken, the number n, would be about 3 
times larger; in such a case a special 
mechanism of electrolysis, as I endeavored 
to sketch it elsewhere, isin question. What 
I wish chiefly to point out, however, is that 
the order of the velocities U and k, ob- 
tained from such widely different experi- 
ments, is about the same. Indeed if one 
supposes that but 1/3 of all the ions travel 
in a given cardinal direction, 3k will replace 
k in the above estimates, and the close 
proximity of 3kand U is even morestriking. 
C. Barvs. 
BROWN UNIVERSITY, Providence, R. I. 
SCIENTIFIC BOOKS. 
Report of the U. S. Commissioner of Patents to 
Congress for the year ending December 31, 
1900. Washington, Government Printing Of- 
fice. 8vo. 1901. Pp. 19. 
Among the many causes which have conspired 
to give the United States its present leading 
SCIENCE. 
503 
position in the industrial world, it may be 
doubted whether any single influence has been 
more potent than that liberal system of patent 
law which was established in the days of Wash- 
ington and Hamilton, and which has been con- 
stantly under revision, usually and until lately 
with improvement, throughout the century. 
That defect which permits the inventor to secure 
a patent upon the simple presentation of a 
written claim, with a drawing or a diagram, 
and without any real work in successful reduc- 
tion of the scheme to practise, and that which 
allows the inventor to secure indefinite reten- 
tion of his legal claim—by the equally simple 
expedient of so wording hisclaims that the ex- 
aminer will be sure to object, taking two years 
to frame another objectional claim, repeating 
this process, until the time is ripe for gathering 
in a profiit—will be remedied whenever the com- 
mittees of Congress choose. The few defects 
in the existing system are capable of instant 
remedy and its excellent features far outweigh 
its faults. That the Congress, the Commis- 
sioner, the public and especially the patent at- 
torneys permit defects to remain is unfortunate ; 
but it remains nevertheless the fact that we have 
the best system of patent-law yet produced and 
that it has done much and is still doing much to 
stimulate invention, to promote the efficiency of 
manufactures and to give prosperity to the 
country and to its average citizen. No more 
important duty lies with the legislative branch 
of the Government than that of sustaining and 
perfecting this code. 
The Commissioner reports annually to the 
Congress. In the report before us hestates the 
total receipts for the year 1900 at $1,350,828.53, 
the expenditures $1,260,019.62 and the profits 
for the year as the balance, $90,808.91. 
The Patent Office has always made a profit 
on its business with the usually poor inventor, 
and this extortion of money from the greatest 
benefactor which this country knows in indus- 
trial fields has permitted the accumulation of 
an enormous sum, now reported ‘by the Com- 
missioner as $5,177,458.55 in the United States 
Treasury, standing at that figure on the books of 
the Treasurer to-day. -In other words, the 
poor inventor has contributed not only thous- 
ands of millions to the wealth of the nation, 
