208 
Excellency in Council will await with interest the reports 
showing the results of the ‘special measures which have 
been adopted in some provinces. It is clear that much 
still remains to be done ; but if sustained efforts are made 
and well-considered plans adopted for the extermination 
of wild beasts and deadly snakes, His Excellency in 
Council believes that the number of deaths from these 
causes will in course of time be materially reduced.— 
Simla, November 8, 1882.” 
From the above it appears that more vigorous mea- 
sures than any hitherto adopted have been taken for the 
destruction of venomous snakes, and the contrast of the 
results of 1881 with those of 1880, warrant the anticipation 
of further benefit if these measures are only carried out 
with a sustained determination to succeed. It is mainly 
a question of perseverance and the expenditure of money, 
and one can hardly imagine a more desirable object 
on which to expend both energy and rupees. But it 
is essential that the system be laid down on some 
general principles for the whole of India, to be worked 
out in detail, according to the needs or peculiarities of 
each district. There should, in short, be a department 
with a responsible chief and subordinate agents, for whom 
certain rules should be laid down to be carried out steadily 
and without hindrance throughout the country, leaving 
much of the detail to the discretion of local authorities. 
I would insist on the importance of carrying it out on 
broad principles everywhere. When such a department 
is constituted under a proper head—and there are many 
persons well fitted for such a duty—then, I believe, veno- } 
mous snakes and other noxious animals will decrease in 
numbers, and people will cease to be startled by these 
appalling losses of life. J. FAYRER 
SIR F. WHITWORTH’S MECHANICAL 
PAPERS * 
HE fact that, by an order in Council of August 26, 
1881, some 300 Whitworth gauges of various dimen- 
sions have been adopted as standards by the Board of 
Trade, is so important a recognition of the value of the 
labours of Sir J. Whitworth in improving mechanical 
measurement, that the occasion has been selected for 
republishing certain papers which have been long well 
known among engineers, but which have not hitherto 
been accessible to the public generally. 
The first paper in the series is on plane metallic sur- 
faces, and the proper mode of preparing them, and con- 
tains an account of an invention of great simplicity, but 
of the highest practical importance. Such plates, when 
worked up to an extreme degree of accuracy and finish, 
form an approximation to a plane surface which would 
surprise and delight any geometrician who had an oppor- 
tunity of critically examining and testing their qualities. 
They consist of an assemblage of minute bright surfaces 
very evenly distributed over a plate of cast iron, and very 
near together. 
As to their qualities, there is not space here to de- 
scribe them, but they have formed the subject-matter of 
an excellent lecture by Prof. Tyndall, at an evening 
meeting of the Royal Institution in the year 1875. 
Passing from these so-called true planes, we refer to a 
step involving an original conception which has led to 
the construction of the new standard gauges. The pro- 
duction of an approximately true plane surface gave an 
increased value and importance to the feeling of contact 
between prepared metallic surfaces, and resulted in the 
invention of a measuring machine which was made to 
depend on the sense of touch instead. of upon optical 
contrivances, and was founded entirely on truth of 
surface. 
* ‘Papers on Mechanical Subjects.’ By Sir Joseph Whitworth, Bart., 
F.R.S., D.C.L, Vol. I. True Planes, Screw Threads, and Standard 
Measures. (London: Spon.) 
NATURE 
[Dec. 28, 1882 
The improvement consisted in the substitution of end 
for line measure, and inasmuch as these are technical 
terms, it may be well to explain them. 
As stated in the last paper of the series, the English 
standard yard is an example of line measure, being 
represented by the interval between two lines drawn 
across two gold studs sunk in a bronze bar about 38 
inches long, the temperature being at 62° Fahrenheit. 
The standard yard, from the subdivisions of which the 
s‘andard inch has been obtained on the Whitworth 
system, is a rectangular metal bar with plane sides 
capable of resting along its whole length in rectangular 
V grooves, which are plane surfaces, while the ends of 
the bar are planes lying perpendicular to its axis. The 
bar is exactly 36 inches long, and the measurement is 
complete when the degree of contact between its ends 
and two small true planes abutting against them is ascer- 
tained. Such a measurement is, of course, end measure, 
and its accuracy depends throughout upon truth of sur- 
face, and also upon truth of position of surface. The 
ends of the bar must be perpendicular to its axis, and 
the planes which feel those ends must be truly parallel to 
each other, and one at least must be movable to and fro 
without deviating at all from the position of parallelism 
to its fixed neighbour, 
Then comes the question of the amount of shifting ot 
the movable plane. That is done by a micrometer screw, 
the linear motion for one graduation of the micrometer 
head, which can be easily read without a lens, being in 
some cases I-10,o00oth of an inch, and in other cases 
I-1,000,000th of an inch. 
There is not space to discuss the measuring machine, 
whether as capable of producing cylindrical gauges 
varying by I-10,o00th of an inch, or as capable of repro- 
ducing a standard inch or a standard yard to a degree of 
| accuracy which leaves the microscope far behind in the 
contest. 
It must suffice to point out that the reprinted papers 
are full of interest, as showing the manner in which Sir J. 
Whitworth has thought out and accomplished the work 
of improving the construction of machinery, and it is 
matter of regret that those who are occupied in teaching 
mechanics have not better opportunities than now exist of 
becoming practically conversant with the subject-matter 
of the collected papers. 
NOTES 
FroM Punta Arenas, near the extremity of South America, 
intelligence has been received that the fourth section of the 
German expedition sent out to observe the transit of Venus has 
been particularly successful, Professor Auvers having managed 
to take exceedingly good photographs and numerous measure- 
ments. 
A TELEGRAM received from Monte Video states that the 
Volage has anchored in these roads from Santa Cruz in Pata- 
gonia. Capt. Fleuriais and observers of the transit of Venus 
were on board, returning to France with their instruments, 
photographs, and other documents. 
M. TREPIED, in a communication to the Paris Academy on 
his observation of the transit in Algiers, states that clouds 
rendered the ordinary observations of little value, but that some 
good results were obtained with the spectroscope on the borders 
of the planet in the region from A to E; while some photographs 
were obtained in the green, the blue, and the violet. The 
examination of the spectral lines in the groups A, B, a, in the 
regions comprised between a, D, E, did not show, M. Trépied 
states, anything which could be attributed to a selective ab- 
sorption produced by an atmosphere on the planet. The same 
inference is deduced from the photographs. 
' 
