1928-03-27 — Page 10

10

Bargains in

Rain Coats!

For Gentlemen

For Ladies -

For Children

$6.50 up

$9.00 up

$5.75 up

Also Special Offer in Gents' & Ladies' Umbrellas.

YEE SANG FAT CO.

Hong Kong's Artistic Photographers PHOTO TAKEN DAY AND NIGHT

The

YING MING STUDIO

No. 50-52, Queen's Road Central. DEVELOPING, PRINTING AND ENLARLING, (Official Photographers of the "China Mail.")

SAND-LIME BRICKS.

Best machine mnde bricks

Highest tests and uniform qualities.

For Economy, Quality, Beauty, Durability and Satisfaction unsurpused.

YEE YICK SAND-LIME BRICK CO.,

CHING IU NAM

Manager.

Factory: Canton. Hong Kong Office, ,148, Queen's Road, West, 1st Floor. Telephone No. C.3882.

CHY LOONG.

New Season. Preserved Ginger. Best quality-Prompt attention to Exporters.

Office: 231, Queen's Road Central, 2nd floor. Tel, Central 2330, Factory: 500-504, Canton Road, Yaumati. Tel K. 869.

BUSINESS DIRECTORY.

Bookbinders.

THE "CHINA MAIL,"

binders.

Book-

No. Sa, Wyndham Street.

Dentist.

HARRY FONG, Dentist,

1st floor, No. 74, Queen's Road Central. Tel. Central No. 1255.

Electrical Supplies.

THE GLOBE FOOK CHEONG

ELECTRICAL SUPPLY CO., LTD. 72, Queen's Road, Central.

Tel. C. 8270.

Engineers &

Shipbuilders.

W. S. BAILEY & CO., LTD.,

Engineers and Shipbuilders,

Kowloon Bay.

Call Flag "L" Bols Agents for Kelvin Motors:

New Work & Repairs.

Hair Dressers &

Booksellers.

LEE YEE,

Ladies' and Gentlemen's

Hair Dressers

and Booksellers.

No. 12, D'Aguilar Street, (opposite Queen's Theatre)

Hair Dressing Saloon.

HANSON SKEY,

Ladies' and Gentlemen's

Firet Class

Hair Dressera.

45, Des Voeux Rd. C., H.K.

THE CHINA MAIL,

RADIO TOPICS

RADIO RECEIVERS.

VARYING THE SIZE OF CONDENSER.

AN IMPORTANT FACTOR.

SOME HINTS ON THEIR ERADICATION.

The movable plates muy touch MICROPHONE NOISES the fixed 'ones and cause the re- celver to be very noisy. It is sur- prising what a number of con- densers are offered for sale that are not really mechanically sound, but on the other hand there are many tuning condensers of excol- lent construction to be obtained at reasonable prices.

#

TO STOP "HOWLING."

The value of a condenser can emitter valves have noticed thei nearly always be determined by tendency at times for a low-toned inspection. If it has large bear-hum to, develop, which may in- ings, a spindle of reasonable thick-crease to a very definite howl if mess, and there la no sign of loosa-

TUESDAY, MARCH 27, 1928.

DAILY CROSS-WORD PUZZLE.

(This cross-word puzzle has been made by an expert

but our readers are warned to look out for occasional

phonetic spellings, such as harbor, plow, and altho.)

פון

5

12

10

10

No doubt, most users of duli-:

13.

14

it

17

10

19

20 121

1122

23

24

25

26

Buy 20

29

130

33

34

135

36

38

39

141

142.

#3

प

ELS

46

[149

50

1551

52

153

SV

55

56 57

158 159

60 16)

62

How the Nolses Are Caused,

The chief offender in the setting up of these noises is the filament of the valve, although vibration of

The tuned circuits of a wireless receiver are composed of cells and condensork, and their size deter- mines the wavelength to which the eircuits tune. If we increase the size of the tuning condenser, forness, the article will probably give the set is knocked, or which may satisfactory service. A proportion oven develop of its own accord example, the wavelength goes up, of the better-class condensers have when the valves are switched on. and the same effect is produced by flexible connection between the This trouble is due to "micro-

movable plates and the frame.

phonic noises, and may, and very increasing the size of the coll.

Fixed and Movable Plates, often does, become a very serious hindrance to loud speaker recep- This is in many respects an ad-tion. The cure, fortunately, ie not vantage, but yet a condenser not very difficult to effect. having a flexible connection of this type is not necessarily likely to prove defective after use. The designer may have provided a rub bing contact sufficient to insure a good connection with the moving the grid or plate may possibly con- plates.

Tuning condensers used, and two tribute. The trouble, which is al- or three years ago, to have fixed most entirely absent in bright and movable plates of roughly a semi-circular shape. When a con-ment operates at a high tempera- denser of this type is used to tune ture, is due to the fact that in dull-emitter valves the heated filn- a coil connected, for example, be-

ment still retains the mechanical tween a high frequency amplifying valve and the detector, the first properties of a stretched wire, and few degrees of the condenser alter ment is not sufficiently heated to is capable of vibrating. The fila-! the wavelength of the circuit by a much larger amount than an equal expand, and lose its elasticity, and movement of the condenser at the the tension must be large enough to prevent any tendency for it to top of the scale.

Tuning is, therefore, not very sag towards the grid. A knock or have turned jar on the bulb of the valve will easy, and designers If the condenser had a smaller their attention to the shape of the start the filament off on a series maximum capacity circuit plates in order that a more uni- of vibrations at its own natural period; but, in this case, the vibra- would not tune to so high a wave form tuning curve should be pra- tions would not be sustained, pro- length, but if the condenser had duced., At the present time there a larger maximum capacity the cir- are three special types of tuning vided that there was no reaction

from the loud-speaker. cuit would tune to above 500 condenser. One of them is known as the "square law," and when metres.

of the

A circuit can, therefore, he tun- ed by varying the size of the con- denser in the circuit or the size of the coil, Modern receivers are usually tuned by means of an ad- justable condenser, but a year or two ago circuits having a fixed con- denser and an, adjustable tuning coll were fairly popular.

Some tuning calls are plug-in type. The tuning. coll. fe usually wound in compact form and fitted with a holder having a brass socket and u contact pin. When one of these coils is used the wavelength range that can be covered by means of an adjustable condenser may be, for example, 300 to 600 metres.

the

emitter valves, in which the fla-

In the most serious cases, which

A circuit comprising a given he is used in a circuit tuning is often occur when a large ampli- coil and adjustable condenser will much more even, there being prac-acation is attempted. the sound therefore tune over a certain bandtically a straight line relation be- waves emanating from the loud- of wavelengths, and when it is de- tween the wavelength and degree speaker appear to react on the de- sired to increase the wavelength on the dial of the condenser. range of the set the coil or the condenser must be increased in aize.

Changing the Coll.

Straight Line Frequency.

tector, or audio-amplifying valves, either through the air or through the table or cabinet. The flament

The "straight line frequency" will respond if the reaction and type is designed to provide equal effect is sufficiently strong to make spacing on a frequency basis, and it vibrate at an

unnatural fre

It is usually more convenient to the third type, known as the quency, and a continuous howl pure low-fre- A receiver in-"logarithmic" is of great assistance will be set up by change the coil. tended for the lower broadcast when a number of circuits have quency reaction. band of wavelengths covering 200 to be tuned simultaneously.

all

Prevention.

to 600 metres, and for the long The Straight line frequency type: The trouble may be overcome by wave stations, between 1,000 and of tuning condenser is not very

far as possible, i preventing. 08 2,000 metres, has therefore to be popular, although they are used provided with two coils. They quite extensively, Amateurs seem vibrations of a frequency corres may be of the plug-in type or to

of the ponding to the natural perfed of prefer condensers wound in the form a single layer. logarithmic type, or even those of the loud-speaker diaphragm reach i when a

switch will have to be the square law type: there is not ing the flament. (It is waves of used in order to cut out the por-much to choose between them when this frequency that have been found by experiment to do the tion of the coil not required for the circuit is a simple one. Many the particular wavelength range. manufacturers make three damage). This is accomplished by The mechanical dimensions of a types, for one does not seem to mounting the valve so that it can- coll do not determine the wave offer very great advantages over not vibrate at any but very low frequencies, valve holders employ- length range over which it can be another in ordinary circuits.

Ing A number of tuning condensere tuned with a given adjustable con- denser. The important factors are are fitted with a slow modern de- the diameter and length of the vice, and others are so designed winding and the number of turns that a slow motion dial may be of wire. If the coll is three used with them. Care must be tendency to howl. inches in diameter and three taken that the reduction gear is inches long, and is wound with 60 not harsh and does not slip, but turns of wire, a condenser of .0005 there are many excellent models to microfarad will tune the circuit choose from.-W. James in "Morn- from approximately 200 to 600 ing Post." metres, but the circuit will tune from about 800 to 1,900 metres

if the coil is wound with 200 turns

of a finer gauge of wire to take the same space.

THE GRID BATTERY.

some, resilient spring or cushioning device being employed, although if the amplification fac- tor is great there may still be a

164

HORIZONTAL

1-Of rich green

nator

s-What Insect was

sacred in assolent + Egypt7 10-InterweaVI 11-What anolent

British-chieftain in the subject of much mythical romance? 13-A variety of checas 15-Revolved, as a

oyclone 17-Chanca

19-Banatul 20-Man's name 22-What is the familiar

name for an Irishman? 24-Halbard-like

weapon (pl.) 26-Worthless leaving

. 29-A large anolent

piatol

31-A romarkable foot

(colloq.) 12-And not

13-What le baby food? 15-Diaposed of by sale 36-A frame of a

window, sat with glat

99-A dance stap 41-To receive

48-A variety of moth

44-What is a skein of

yarn containing 120 yarde? 48-8ooner than

47-To crimp agulri

HÁN ÖTHE INTERNATIONAL SYNDICATE

VERTICAL (Cont.)

HORIZONTAL (Cont)

[50-A foot of an animal) 16-To disclose

| 82-Raw instal

53-Relative (abbr.) 84-To be off one's,

guard 56-What is the stalen

of a vowal or syllable from the midst of a word? 60-Concoded facts 62-Clergyman 63-Flowed 64-What mountain in

N. California le the second highest|

In the U. 8.7 66-What Britan

statesman was High, Lord Chancellor 1912-19167

VERTICAL

t-Who was. New

England's most famous essayist? 2-Ingano.

3-A settlement on the

W. Comst of,

Greenland

4-To move slowly 6-Arld

18-A tablet 21-To give |25-What in the"

principal.desaand- Ing-root of a plant? 28-A Japanese

statesman 27-Redder 28-An ecstasy (pl.) [30-A breach

34-Equivalence 97-Serien (abbr.) 18-A mat to contain the

hair

|40-The vital fuld of a

pinnt

|42-A region considered

with reference to some special

рогрове

43-Angles with rad and

recl

|46¬A ̈sylvan deity 48-What la the capital

of Hejaz, W. Arabla?

49-To make a map or

shart of

61-To press Into

6-What auxiliary verb)55-An estuary of the

expresnės simpto

futurity?

7-A sword-like

weapon

B-A metric land-

measure

-To bear the brunt of 12-Trim

14-A chart

Amazon river

{87-Timo-perinde

(abbr.)

58-Interjection,

Contempt

|59-A notabla period of

tima

61–70 harden, as fluf.

nets or sulla

(Tre solution of the above cross-word puzzle will

appear in to-morrow's issue along with a new cross-word

puzzle.)

WATER SUPPLY.

Level and Storage of water in Reservoirs on March 1, 1928:

CITY AND HILL DISTRICT WATER WORKS LEVEL.

Tytam Tytam Byewash

Tytam Intermediate Tytam Tok Wong Nel Chung Pokfulum

1027 1928 271,21 291.70

$9.52

72.87

865.00

€50.02

10.65

0.02

23,80 23.25

YESTERDAY'S SOLUTION.

FA ILL

RAM

ER

GAIN BŘINGS.

THRE

RN.

HO TZANNEX MEAN TORIES

ATH

LONE EAR

YELLED SORDOS

REEL

SCHE INTERNATIONAL STRUGATE

•KOWLOON WATER WORKS

LEVEL.

1027 1928 Kowloon Reservoir. 15' 7"B 8' 10"B Shok Lai Pui Roser-

voir

10' 2" 2' 4"B Reception Reservoir 3' 4" 6' 8"B

Storage in millions and decimalu

A further precaution would be to surround the valves with an

1927/ 1928 open cylinder af cardboard, which

Tytam

14' 9"B 11' 10"B would shield it directly from the disturbing waves. Removal of the Tytam Byewash...28 2′′B 26' BPB loud-speakers from the proximity Tytam Intermediate 20' 4"B 27' 11"B of the set to a considerable dis- Tytam Tuk ....25′ 10′′B 88' 6"B tance will also minimise the trou- Wong Nei Chung..19 18 20 4"B „20′ 4′′B 20′ 7′′E Poktulum ble, or, if it is only alightly pre-

iNote: B. denoter "Below Overflow": sent, turning the horn of the loud-

A denoten "Above Overflow."] speaker so that it directs the Some coils are more efficient

Storage in millions and Yelmals than others. A single layer coil One of the things that puzzles sound away from the valves will

of gallone. for the lower broadcast band of the beginner with wireless is that be effective in stopping the trou- wavelengths can be made more his grid bias battery does not run ble. efficient than a plug-in multi-lay-down in the same way as the high- er type of coil, but for the wave- tension battery after a few months'

of gallons. length range

of about 1,000 to use. If the beginner has a testing

1927 1028 2,000 metros, a good plug-in coll instrument, he is inclined to test structor will very often use a cell

200.78 Kowloon Reservoir... 210,6 is usually superior to a compact it faithfully every few weeks, and taken from a flash lamp battery.

Shek Lal Pul Reservoir 88.14 100.08 CO.single-layer one.

is somewhat surprised to find that Such a cell will work quite ade-

Total 1,270.08 1,047.76 Reception Reservoir 24.55 81.30 it keeps on giving a full reading, quately, but it is essential to look

Consumption of water in the City Tuning Condensers. After a while, however, he realises at it every month or so, and to and Hill District in millions and de-

207.74 404.86 particular Tuning condensers do not vary that this

component replace it as soon as it begins to cimais of gallons during the month of Printers.

greatly in efficiency. One type is really does last a long time, and, fall. If this is neglected the February.

variation in the voltage will cause

1027 1928 "THE CUINA MAIL," Genera: usually as good as another from ultimately he forgets to test it.

191.80 204.54 Printers.

an electrical point of view. But This is particularly true of the a considerable falling of in signal Consumption....... not all tuning condensers are good small one call battery which is strength, and the increased resist- Estimated population 409,340 419.000

10.8 ones. Some of them are so made often tucked away inside a set to ance of the cell will render the set Consumption per head that they cannot be. turned give a negative bias to a high-fre- unstable.

Full Supply in all Rider Main Dia- It is a good plan in any case tricts during February with the excep smoothly. Others have bearings quency, valve or to a bottom-bend that are a little too large for the detector. If this cell is of sturdy to shunt such a battery by a fix-tion of the district west of Garden-road spindle to which the movable build, and from a reliable manu-ed condenser, preferably one with plates are attached. Condensers facturer, it will last two years at a mica dielectric, and with as large having this fault are sure to give least, but the beginner who has a capacity above .002 mfd, as pos- trouble after a period of use. progressed to the stage of a con- sible.

Optician.

THE HONG KONG OPTICAL

'Phone 2232,

68, Queen's Road Central.

Publishers and Bookbinders.

3a, Wyndham Street. Tel. C. 22. Ship Chandlers.

E. KING & CO.,

25, Wing Wa St. Tel. C. 1116 Metal Merchants and Shir

Chandlers. Managing Director-

per day

16.7

where an Intermittent supply was Intermittent supply in all Rider given from 3rd to 28th February, 1927. Main Districts during February, 1928.

Total

Consumption of water in Kowloon in millions and decimals of zailoru dur. ing the month of February,

1027 1928

84.59 04.04. Consumption........ Estimated population 158,980 184.020 Consumption per head par day .................................

14.5 10.6 Full Supply in all districts during February 1927 and 1928.

The Government Analyst's report

satisfactory. show that the quality of the water in

Total rainfall to February 28, 1927, 4.66, February 29, 1028, 6.45.

Whitfield King & Co.'s 1928

Standard Catalogue.

of

POSTAGE STAMPS

of the World

with 5,625. Illustrations

at $3 each

GRACA & CO. Dealers in Philatelic Goods

DHAM STREET,

HELLO MIKE- KIN YOU COME OVER? THE FOLKS ARE OUT• I'VE COOKED SOME CORNED BEEF AN CABBAGE - COMB, RIGHT AWAY:

BRINGING UP FATHER.

THERE IT IS MY IT

SMELLS GOOD-THERE

GOES THE FRONT

DOOR BELL HE

GOT HERE

QUICKLY-

STRANGE!

NO ONE

HERE!

WHAT DO YOU KNOW ABOUT

THAT? THE CORNED BEEF ́AN' CABBAGE IS GONE!