Stationary electric waves on a spiral wire, and compared the distance of the nodes with the corresponding distances when the wire was stretched out straight. Theoretical treatment has been given by H. C. Pocklington, and G. Siebt has provided lecture apparatus for exhibiting the propagation of stationary waves on spiral wires.

The first experiments described by the author were made with a long helix of insulated copper wire, wound in one layer on a wooden rod. The helix consisted of 5,000 turns, the length being 200 centimetres. If such a helix is placed in connection with an oscillating circuit consisting of a condenser or Leyden jar, a spark gap and a variable inductance, stationary waves could be set up on the helix by adjusting the inductance in the oscillating circuit. In order to detect the nodes and antinodes of these stationary oscillations, the author makes use of a vacuum tube, similar to that used in spectrum analysis, preferably one filled with the rare gas, Neon, which was kindly supplied to him by Sir William Ramsay. Rarified Neon seems to be extremely sensitive to the presence of variable electric force through it; hence, if such a tube is held perpendicular to the helix and moved parallel to itself along it, it glows brightly at the antinodes, but not at the nodes. In this manner the internodal distances can be measured with considerable accuracy, and the wave-length of the stationary oscillation measured.

The paper also contains a theoretical analysis of the phenomena leading to the conclusion that the velocity with which the wave is propagated along the spiral is inversely proportional to the square root of the product of the capacity and inductance of the helix per unit of length. The author has perfected of late years methods for measuring very small capacities aud inductances, and in the case of the above-named helix the inductance is equal to 100,000 centimetres per centimetre, whilst a capacity of the helix is of a micro-microfarad. (1 micro-microfarad 10-6 microfarad.)

From these data the propagation of electric waves along the helix can be shown to be 235,000,000 centimetres per second. This figure is confirmed in the following manner :-The capacity and the inductance in the oscillating circuit are both measured when the first harmonic oscillation is formed on the helix, and under those conditions the half-wave length was found to be 140 centimetres, whilst the frequency in the oscillating circuit, as calculated from the capacity and inductance, was found to be 0.847 X 106. Having, therefore, the wave-length and frequency, we find their product gives a velocity of 235,000,000 centimetres per second, which agrees with the figure determined from the constants of the helix.

It is shown in the paper that the best form of inductance to be employed in connection with the oscillating circuit is a square of one turn of wire, and that the employment of spiral coils leads to errors due to passage of a dielectric current from coil to coil. On the above lines an apparatus has been

devised by the author for measuring wave-lengths in connection with Hertzian wave wireless telegraphy. It is a matter of considerable importance to be able to determine the frequency and wave-length of the waves sent out by any given transmitting arrange

ment.

The author calls this instrument a "Kummeter." It is constructed as follows:-A long ebonite rod is wound over closely with silk-covered wire in one layer, and this is supported on insulating stands. On this long helix slides a metal saddle having some layers of tinfoil interposed to make good contact between the saddle and the helix. This saddle is connected by a flexible wire with the earth. One end of the helix is furnished with an insulated metal plate, which is placed in apposition to another metal plate fixed to the oscillating surface of the transmitter. The process of measuring the wave consists in sliding the saddle along a Neon vacuum tube, indicates the presence of one node halfway between the saddle and the plate. When this is the case the distance from saddle to plate is one wave-length of the stationary wave on the helix.

From the constants of the helix the velocity of the wave along it can be calculated as above shown, and hence the frequency of the oscillating circuit becomes known. If this frequency is divided into the velocity of light, reckoned in feet, it gives the wave-length in feet of the wave radiated from the associated aërial, provided that the aërial radiating wire has been tuned to be in resonance with this oscillating circuit. This instrument also provides the means of measuring small inductances, and also the frequencies in oscillating circuits, which are much higher than those which can be determined by photographing the spark.

ADMIRALTY CHARTS.

The following is the official list of charts issued by the Hydrographic Department of the Admiralty in July and August last :

New Charts.-No. 1683-England, west coast; Padstow harbour. 1919-Scotland; Hebrides, Lewis island: Stornoway harbour. 3400 England; Channel islands :-Guernsey, Herm, and Sark. 3442-Lapland; plans on the north coast of Russian Lapland :- Ivanovski bay. 3435-Sweden; plans on the east coast:-The narrows of Kalmar sound; entrance to Gefle; entrance to Umea. 3414-France, south coast-approaches to Marseilles. 2285Black sea; Varna :-Baljik bay. 3406-Newfoundland, east coast:-Bay of Exploits, Sheet I. (North). 3417 British Columbia; Vancouver island :Hanson island to Beaver harbour, including Broughton strait; Port McNeill. 3431-Africa, west coast:-Cape Coast Castle to Barako point. 3432Africa, west coast :-Barako point to Great Ningo. 3423-Africa, west coast:- -Old Calabar river, Duke town anchorage. 3370-Philippine islands :-San Bernardino strait and approaches. 3429-China,

:

-

east coast; Hong Kong island:-East Lamma channel. 3437-Japan; Nipon, west coast:- Hagi approaches. 431 - Australia, west coast:-Swan river, North Fremantle to Perth. 1347 - Peru; plans on the coast; plan added:-Huacho anchorage. 632-Africa, west coast; Walfisch bay to Orange river; plan added:-Prince of Wales bay. 1341Eastern archipelago; anchorages on the north coast of Java; plan added:-Tegal road. 1023-China, south coast; Boddam cove; plan added:-Nam sha bay. 1256-China, north coast; Gulfs of Pe chili and Liau tung; plan added:-Sketch of entrance and bar of the Yang kiao ko.

Charts that have received additions or corrections too large to be conveniently inserted by hand:— Nos. 1188-The World :-Coal and telegraph chart. 34-England, south coast:-The Scilly Isles. 1765 -Ireland, south coast:-Queenstown and port of Cork (outer sheet). 1777-Ireland, south coast:Queenstown and port (inner sheet). 3384-Ireland, south coast:-Queenstown. 2246-Baltic sea :Port Baltic to Hogland. 2694-France, west coast: -Channels between Ile d'Ouessant and the mainland. 2554-Mediterranean Sea; Italy :-Leghorn roadstead, &c. 2379-Black Sea :-Kherson Dnieper bay. 893-Newfoundland :-Burin harbour to Devil bay. West India islands and Caribbean sea, sheet I. 762-West Indies:-Jamaica and the Petro bank. 1274-Gulf of Mexico :-Tortugas cays to cape San Blas. 23-Chile: - Channels between Magellan strait and gulf of Trinidad. 631-South America, west coast :-Smyth channel from south entrance to Fortune bay. 1840-British Columbia :-Haro strait and Middle channel. 759a-Madagascar:-Cape St. Andrew to Bevato island. 821-Bay of Bengal:Elephant point to Cheduba strait. 833-Bay of Bengal:-Rangoon river and approaches. 2153Malacca strait: - Port Swettenham. 928 - Sulu archipelago. 2577-Philippine islands:-Between St. Bernadino and Mindoro straits. 3283-Philippine islands-Port Salomague and approach; port Sual. 127-Japan :- Hirado no seto to Simonoseki strait. 1674-Australia, east coast:-Brisbane river. 2614-New Zealand :-Kaipara harbour. 2540New Zealand:-Awarua or Bluff harbour and New river. 3044 Celebes:-Ujong Jonga to Ujong kassi.

These charts are issued by Mr. J. D. Potter, 145, Minories.

General Notes.

HOUSES OF HISTORIC INTEREST.-At the meeting of the London County Council, held on the 25th October, it was agreed, upon the recommendation of the Local Government and Records Committee, to affix a memorial tablet at No. 23, Suffolk-street, W., where Richard Cobden lived. The committee re

ported that the Duke of Bedford had fixed tablets at his own expense at the following houses on his estate :-65, Russell-square (Sir Thomas Lawrence), II, Bedford-square (Henry Cavendish), 6, Bloomsbury-square (Isaac D'Israeli), 28 and 29, Bloomsburysquare (Lord Mansfield), 43, King-street, Coventgarden (Admiral Lord Orford), 27, Southamptonstreet, Covent-garden (David Garrick).

MEETINGS FOR THE ENSUING WEEK. MONDAY, OCT. 31...Farmers' Club, 2, Whitehall-court, S.W., 31 p.m. Mr. C. Harris Stratton, "An Outsider's View of the Management of Local Affairs by County Councils,"

London Institution, Finsbury-circus, E.C., 5 p.m.
Lord Avebury, "Our Fiscal Policy."

TUESDAY, NOV. 1...Central Chamber of Agriculture (at the
HOUSE OF THE SOCIETY OF ARTS), II a.m.
Civil Engineers, 25, Great George-street, S.W.,
8 p.m. Opening Address by the President, Sir
Guilford Molesworth, and Reception.
Horticultural, Vincent-square, Westminster, S.W.,
I p.m. Exhibition of Autumn Flowers; 3 p.m.,
Lecture.

"

THURSDAY, Nov. 3...Tramways and Light Railways Assoc. (at the HOUSE OF THE SOCIETY OF ARTS), 8 p.m. Mr. A. N. Connett, Notes on Permanent Way." Chemical, Burlington - house, W., 5 p.m. I. Messrs. J. B. Cohen and J. Gatecliff, "Note on the Action of Nitric Acid on the Ethers." 2. Mr. E. A. Werner, "The Condensation of Formaldehyde with Acetone." Preliminary Note. 3. Mr. J. W. Mellor, "Union of Hydrogen and Chlorine.-Rate of Decay of Activity of Chlorine." 4. Messrs. S. S. Pickles and C. Weizmann, "The Action of Phthalic Anhydride on a naphthyl-magnesiumbromide." 5. Mr. O. Silberrad, "The Constitution of Nitrogen Iodide." 6. Mr. H. Ingle "The Available Plant Food in Soils." 7. Messrs. W. A. Bone and R. V. Wheeler, "The Combustion of Ethylene." 8. Mr. C. E. Fawsitt, "The Decomposition of Methelurea." 9. Miss E. G. Willcock, "The Influence of Certain Salts and Organic Bodies on the Oxidation of Guaiacum." 10. Mr. J. A. N. Friend, "The Influence of potas sium Persulphate on the Estimation of Hydrogen Peroxide." 11. Messrs. R. S. Morrell and E. K. Hanson, "The Dynamic Isomerism of a and Crotonic Acids." Preliminary note. 12. Mr. W. A. Caldecott, "The Influence of Sunlight on the Dissolving of Gold in an Aqueous Solution of Potassium Cyanide." 13. Mr. H. D. Dakin, a. "The Fractional Hydrolysis of Amygdalinic Acid." b. "Isoamygdaline."

London Institution. Finsbury-circus, E.C., 6 p.m.
Sir Robert Anderson, "Crime and Criminals."
Camera Club, Charing-cross-road, W.C, 8 p.m.
Lecture by the President, Sir William Abney.

FRIDAY, Nov. 4...Art Workers' Guild, Clifford's-inn Hall,
Fleet street, E.C., 8 p.m.

Geologists' Association, University College, W.C., 8 p.m. Conversazione,

COLONIAL SECTION.

January 24, February 28, March 28, May 23.

The following courses of Cantor Lectures will be delivered on Monday evenings, at 8 o'clock:

DAVID JAMES BLAIKLEY, "Musical Wind Instruments." Four Lectures (with musical illustrations).

LECTURE I.-NOVEMBER 28. IntroductionMusic and the practical arts-Division of instruments into string, wind, and percussion-Limitation of definition-Wind instruments and the human voiceAcoustics and the art of instrument making-Vibration and wave motion-Every wind instrument a vibrating column of air-Stationary waves-Means of exciting vibration-Wave-form-Classification into brass, reed, and flute.

LECTURE II.—DECEMBER 5.-Brass Instruments. -Primitive instruments from horns and shellsHarmonic scale-Development into bugle and trumpet types-natural horns and trumpets-Introduction of slides, keys, and valves,

The Council of the Society of Arts hold a sum of £400, the balance of the subscriptions to the Owen Jones Memorial Fund, presented to them by the Memorial Committee, on condition of their spending the interest thereof in prizes to "Students of the Schools of Art who, in annual competition, produce the best designs for Household Furniture, Carpets, Wallpapers, and Hangings, Damasks, Chintzes &c., regulated by the principals laid down by Owen Jones."

The prizes will be awarded on the results of the annual competition of the Board of Education, South Kensington. Competing designs must be marked "In competition for the Owen Jones Prizes."

No candidate who has gained one of the above prizes can again take part in the competition.

The next award will be made in 1905, when six prizes are offered for competition, each prize to consist of a bound copy of Owen Jones's "Principles of Design," and the Society's Bronze Medal.

Proceedings of the Society.

THE MAJOLICA AND GLAZED EARTHENWARE OF TUSCANY.

BY PROF. R. LANGTON DOUGLAS, M.A.

Lecture III.-Delivered May 9th, 1904. CAFAGGIOLO AND THE LATER HISTORY OF

CERAMICS IN TUSCANY.

"We believe," writes Professor Malagola, "that the place Cafaggiolo is destined to dis appear for ever from ceramic history." "We are convinced," writes his friend Professor Argnani, "that the fabbrica of Cafaggiolo of Tuscany has had its origin and its existence only in the minds of certain authors by reason of a kind of mono-mania."

These two learned writers asserted that the pieces signed "In Chafaggiolo" were really made not at the castle in the Mugello, but at an imaginary fabbrica at Faenza styled Casa or Ca' Fagioli. It is worthy of remark that this last theory was not originated by Professor Malagola, and that its true author, the late Dr. Frati, lived to deride it. I have often heard my kind old friend now lost to us laugh over this fantasy of his earlier days, and condemn the parochial patriotism of those Faventine historians who clung to it after it was discredited. Campanilismoparochial patriotism-has been responsible for three-quarters of the fatuous theories that disfigure the pages of Italian works relating to history, art, and archæology. Campanilismo led the Sienese writers of the 17th century to maintain that Sodoma was born not at Vercelli in Piedmont, but at Vergelle, a little Tuscan village. It led Tuscan writers of the 19th century to contend that Niccolò Pisano was born not in Apulia, but in Puglia, a little village near Lucca. It impelled Neapolitans to assert that the lovely altar-piece, “S. Louis crowning King Robert," in their church of S. Lorenzo was not the work of Simone Martini, of Siena, but of some visionary Simone Napoletano. It led the Florentines to post-date the career of Duccio of Siena, and to give one of his greatest works to Cimabue, and to assert that Ugolino and Simone Martini were pupils of Giotto. But amongst all these manifestations there has been nothing to equal the performances of the Faventine writers on majolica, who have declared that the great and

ancient Sienese pottery was a late-born child of Faenza, and that Cafaggiolo was the Mrs. Harris of ceramics. With the assistance of my friend, the Cavaliere Alessandro Lisini, I have been able to do something to restore Siena to her proper place in the history of the art. It is to the credit of the late Gaetano Milanesi and Gaetano Guasti that Cafaggiolo has been given its rightful position amongst the fabbriche of Central Italy.

In this lecture I will tell the true story of the pottery of Cafaggiolo, as it is revealed to us in the documents discovered by the two distinguished scholars to whom I have just referred, in the signed productions of the fabbrica, and in the pieces which considerations of style have led me to regard as being the work of the artists who made these signed pieces. And first I will say something about the artistic parent of Cafaggiolo, Montelupo.

In a gorge of the Arno valley, between Florence and Empoli, stands tower - crowned Montelupo, guarding the high road from the capital to its sea-port. Montelupo was in all probability a very early centre of the manufacture of majolica. Already in the year 1426 Bartolomeo di Simone of Montelupo practised the art in Florence, under the patronage of the Medici, and at the close of the century the greater part of the inhabitants of the castle of Montelupo were potters. In the statutes of the Guild, dated May 3, 1510, we find the names of no less than thirty-four master-potters. Potters of Montelupo practised their art in Florence, Rome, Pisa, and Cafaggiolo. the same manner, in the 16th century, artists from Faenza found their way to Montelupo.

In

The most important family of artists that took their origin from Montelupo was that of the Fattorini. We first find mention of this family in a document of the year 1469, from which we learn that Filippo di Rimiteri (or Demetrius) was practising the art of the potter in Montelupo. This Philip was a native of Zagabria in Croatia, where he first saw the light in 1403. He had two sons

Piero, born in 1445, and Stefano, born in 1458-both of whom practised their father's art. Philip died in the eighth decade of the 15th century; for in the year 1480 Piero appears as head of the family of the Fattorini, who, under the patronage of Lorenzo di Pierfrancesco de' Medici and Pierfrancesco, his son, became the founders of the pottery of Cafaggiolo.

Lorenzo di Pierfrancesco de' Medici belonged to the junior branch of the house of