AGA REPORT—1899. 
The full report on the results of the expedition, shortly to be published 
as a special volume at the expense of the Liverpool Museums, will contain 
a Narrative of the Expedition, and complete lists, with coloured figures of 
all the new species, of the fauna and flora of the islands visited, with 
notes on their Geology and Anthropology. 
Small Screw Gauge.—Report of the Committee, consisting of Sir 
W. H. Preece (Chairman), Lord KeEtviy, Sir F. J. BRAMWELL, 
Sir H. Trueman Woop, Major-Gen. WEBBER, Col. WATKIN, Messrs. 
Conrap W. Cooke. R. E. Crompron, A. Strow, A. Le NEVE 
Foster, C. J. Hewitt, G. K. B. Expninsrone, T. Buckney, 
E. Rice, C. V. Boys, and W. A. Price (Secretary), appointed 
to consider means by which practical effect can be gwen to the 
Introduction of the B.A. Screw Gauge. 
ApPENDIX.—Reports on Screns made by the Pratt and Witney Company :— 
I. By Colonel WATKIN . . ; . : : . : 466 
II. By Mr. H. J. CHANEY . ; : . ; : : - z . 468 
In 1882 a Committee was appointed by the Association to determine a 
gauge for the manufacture of the various small screws used in telegraphic 
and electrical apparatus, in clockwork, and for other analogous purposes. 
This Committee reported to Section G in the succeeding years 1883, 1884, 
and proposed that a certain system of screw-threads, since known as the 
British Association screw-threads, should be recommended for adoption 
by users of small screws in this country. The system is identical except 
in one small point with that used in Switzerland and associated with 
the name of Professor M. Thury. The series consists of 26 threads, 
numbered 0-25, having diameters from 6mm. down to ‘25mm., and is so 
closely graduated that only in exceptional cases can any size be required 
intermediate between two of the set. The form of the thread has proved 
to be well adapted for practical purposes, and screws made on this system 
have come into extensive use among English manufacturers of small 
mechanical apparatus. It has been adopted by several Government 
Departments, who have imposed its use upon their contractors. 
In the year 1895 representations were made to the Section, and some 
correspondents of the Technical papers urged, that the value of this system 
was prejudiced by the fact that purchasers of British Association screws 
and screwing-tools could not rely on obtaining from manufacturers goods 
which were interchangeable with one another. This raised at once a 
question which had not been closely considered by the 1882 Committee— 
viz., the mode of determining whether any given screw of a particular 
number is or is not a fair representation of the form laid down by the 
British Association specification. The present Committee were appointed 
at the Ipswich Meeting to deal with this point, and with some additional 
members have sat at intervals up to the present time. 
Tn 1896 an interim report was presented to Section G at the Liverpool 
Meeting, in which the problem of the mode of gauging small screws was 
discussed at length. The principal conclusion reached at that time was 
that as no means exists of examining a nut or female screw, the efforts of 
the Committee should be directed to obtaining accurate plug or male screws 
for use as gauges, and combs or chasers. 
During the three years that have elapsed since this report was made 
