that machine-made screws will enter the nuts or tapped holes. The outline of this is ABEGLOQTU.

D. A notch gauge to test the core diameters of male screws.

E. A hole limit gauge to test crest diameters of male screws and to be checked by piece A. The diameter of this is diameter D, fig. 1, Schedule I.

F. A cylinder plug gauge to test the diameter of the hole in the gauge nut C in commercial nuts or tapped holes.

The diameter of this is diameter C, fig. 1, Schedule I.

2. That the standard B.A. screw be defined as a screw which conforms to the gauges described above in all respects except in the form of the crest and root of the thread, which are unimportant.

R. E. CROMPTON.

J. M. GORHAM.

G. K. B. ELPHINSTONE.
MARK BARR.

C. VERNON Boys.

O. P. CLEMENTS.

W. A. PRICE.

APPENDIX.

The Committee have had constructed for them by the Cambridge Scientific Instrument Company a machine for measuring small screws microscopically. In figs. 4 and 5 are given drawings of the instrument, of which fig. 4 is a plan of the compound stage with the microscope removed, and fig. 5 is an end elevation showing the arrangement of the microscope. The screw to be measured is held in a spring chuck in the spindle (Â). By means of the two micrometer screws, S, S2, the screw is moved along geometric slides in two directions at right angles. The screw is aligned parallel to the micrometer S, by the adjusting screws B C. The pitch of the micrometer screws (which were supplied by the Browne and Sharpe Company) is 0.5 mm., and the heads are divided into fifty parts, enabling readings to be taken directly to 0.01 mm.

The screw is illuminated from below by a plane mirror and is observed by the microscope M. Rough focussing is effected by sliding the microscope in the tube T, the fine adjustment being accomplished by the micrometer screw S3, which raises and lowers T. The tube T can also be rotated about its axis without disturbing the focus, and the amount of rotation measured by means of a scale on D. The eyepiece and objectglass of the microscope are by Zeiss. The eyepiece is furnished with

suitable cross-wires in silver.

A series of spring chucks for different diameters of screws accompanied the machine.

FIG. 4.

Anthropometric Investigation in Great Britain and Ireland.-Report of a Committee consisting of Professor J. CLELAND (Chairman), Mr. J. GRAY (Secretary), Dr. T. H. BRYCE, Professor D. J. CUNNINGHAM, Professor A. F. DIXON, Mr. E. N. FALLAIZE, Dr. A. C. HADDON, Dr. D. HEPBURN, and Mr. J. L. MYRES.

THE following circular, which was sent to certain persons and institutions known to be engaged in anthropometric work in the British Isles, and to a few of the more distinguished physical anthropologists in foreign countries, will explain the objects for which the Committee was formed: :

British Association for the Advancement of Science.

1903.

DEAR SIR,

A Committee, consisting of Professor J. Cleland (Chairman), Mr. J. Gray (Secretary), Dr. T. H. Bryce, Professor J. D. Cunningham, Professor A. F. Dixon, Mr. E. N. Fallaize, Dr. A. C. Haddon, Dr. D. Hepburn, and Mr. J. L. Myres, has been appointed by this Association to organise Anthropometric Investigation in Great Britain and Ireland.

The objects which the Committee have in view may briefly be stated to be as follows:

1. To establish uniform standards in Anthropometric Investigation. 2. To ascertain which measurements are likely to prove the most fruitful in result.

3. To formulate broad lines of co-operation,

Much valuable work done in various parts of the country in this branch of Anthropological Science is at present very imperfectly utilised, owing to the difficulty of obtaining information as to the centres at which it is carried on, and because different methods of measurement are employed at different centres. The Committee, therefore, think it desirable to obtain information regarding these methods, in order to consider which are most to be recommended for utility, accuracy, and convenience, and in the hope that a consistent scheme may be formulated for general use throughout Great Britain and Ireland.

For this purpose certain questions have been drawn up, which will be found on the annexed sheet, and I am desired by the Committee to request your co-operation in furthering its objects by answering these questions. and returning your answers to me at your early convenience.

I am,

Yours faithfully,

All communications should be addressed to me:

Anthropological Institute,

J. GRAY.

3 Hanover Square,

London, W,

1. Are you engaged in any anthropometric investigations? If so, what measurements do you usually take, and what classes of people have you measured ? (Enclose copy of Schedule in use, if any, adding description of exact mode of measurement.)

2. What instruments are you accustomed to use for making the measurements ?

3. When were the measurements first taken, and over how long a period are your records of measurements available?

4. Are the measurements published? If so, in what form, in full or in abstract? If in abstract, are the original records available?

5, With what object have the observations been made-e.g. identification; registration of growth; detection of racial differences; correlation with occupations; determination of influence of relationships; or other purpose?

6. Have assistants been employed in making any of the measurements ? If so, have they received any special training, and of what kind?

7. How far do you regard the results which you have obtained hitherto as satisfactory; and what modifications, if any, are suggested by your past experience?

8. Add any remarks not falling within the previous headings.

Forty-seven circulars were sent out and sixteen replies were received, A summary of the replies is given in the Appendix.

The following remarks and suggestions originating out of the Secretary's report have been drawn up by the Chairman of the Committee :

Remarks and Suggestions by Professor CLELAND.

It is disappointing that so few answers have been given in response to the Committee's circular, and that those which have been sent show in so many cases work confined to certain departments of Anthropometry to the exclusion of others; but, having been kindly furnished by our Secretary and Reporter, Mr. Gray, with a sight of the materials at his disposal, I cannot refrain from expressing my belief that he has made out of them as much as could be made,

So far as explicit answers to the questions in our circular are concerned, the Committee cannot be said to have been very successful, but the absence of direct results in that respect suggests the question how far this or some such Committee may be of use by itself proposing some such method of research as may with advantage be generally adopted with a view to the facilitation and organisation of research.

The following suggestions occur to me :-

1. Inasmuch as age and sex are of themselves sources of variations of most distinct descriptions, I should say that, except for the purpose of studying these two kinds of variations, measurements should all be made on males not younger than 30 years and not older than about 45. I have shown in the Philosophic Transactions' many years ago that the male growth is typical, and that the deviations which occur in the female are inconstant in nature and degree. I base my recommendation, both in respect of age and of sex, on my own experience in craniometry, but I would extend it to measurements of all parts of the body.

In this case state at what intervals the measurements were repeated.