Imagens das páginas
[merged small][graphic][merged small]


All communications for the Optical Department should be addressed to

is divided with the other departments of your busiL. G. AMSDEN, 34 Adelaide St. W.

Complete privacy is a necessity in the higher

forms of refraction work. You must be alone with From numerous enquiries received regarding the

your profession and your patient. best way of arranging an optical department, and

A small amount of space and correspondingly from observations made during a recent trip among

small expense is all that is necessary to arrange a the optical trade, I am assured that due importance

model optical room. Four feet wide by twenty two has not been given to this feature of an optical out

in length, with walls and ceiling painted or papered fit. Many opticians are content to find a space of

a dead black, entirely bereft of pictures or other orfifteen or twenty feet, and hang their test type at one

namentation, constitutes an ideal refraction room, end or lean it against the prescription counter, and

The type should hang at right angles to the line locate their trial case on a packing case at the other

of vision and of equal length with the patient's head, and they are ready for business.

and two or more sets should be kept convenient for This is a great mistake, which will go far toward

changing when one is becoming too well known. A neutralizing any ordinary amount of ability as a re

very convenient holder can be made out of an ordinfractionist.

ary wooden box by fastening a type card on each It has two features that are bad. First, the ap

face and passing a rod through the centre on which pearance is so non-professional that the public natur

it can revolve by means of a wire or string connected alty sum up the situation to indicate that the optical

with the operator. department of your business is so decidedly a side

The lights should be arranged to shine on the issue, that the chances of getting good optical work

type while being screened from the patient; whether are very slim.

artifical or sunlight it should be as nearly uniform as You bestow careful attention on your prescription possible. Attention can well be bestowed upon an utensils, your shelves with their rows of fancy decor

operating chair. Frequently examinations are long ated bottles worthy of an art pottery, but for the eye

and tedious, and anything that is conducive to the work “any old place” that is large enough and light

comfort of the patient will assist materially in arrivenough. If you do not consider the optical feature

ing at sound conclusions and accurate diagnosis. of sufficient importance to warrant any attention to

Finally the moral effect of a well arranged and the proprieties, how can you expect the public to give scientifically constructed optical room goes such a it any more concern than you do yourself.

long way towards producing in the mind of your Then there is the question of results, which, after

patient that feeling of awe and confidence in sublime you have induced your customers to overlook the

art and its advocate-yourself—that the case is half unfavorable appearances, are largely affected by the

fitted before begun and they may possibly not reconditions under which you conduct your examin

cover in time to raise even a mild protest against a ation.

good heavy charge. Seated in a public part of your store with those who pass in and out bestowing curious glances or

OUR OPTICAL CLASS. possibly venturing a remark, you cannot possibly expect to retain the attention of your patient, and the

REFRACTION OF LIGHT, (Continued). answers must be consequently misleading. Possibly the light is shaded by customers passing

G. AMSDEN, INSTRUCTOR. in and out, consequently the visual acuteness will It has been found by experiment that a certain show a variation. Your own attention, also, cannot amount of space requires to be included within the possibly be devoted exclusively to your case while it dimensions of the image, in order that perfect de.


velopment of vision may result. The mere fact of an of normal vision. object being exposed in front of the eye is sufficient

SPHERICAL ABBERATION to reproduce its image in the interior, but for subse

Although it has been stated that the refraction of quent' nervous action necessary to develop the a spherical lens is the same for all rays of the same image into an idea, certain sized images are neces

obliquity, this is true in a limited sense only. The sary. While we are unable to state what amount of

axis ray passing through the optical centre under

goes no refraction whatever, as at this point both surface must be included in the retinal image, we do

surfaces of the lens are parallel. The refraction know how large a visual angle is required to insure gradually increases the farther we travel from the the perfect development of the retinal pictures. optical centre towards the edge of the lens, so that The object must be of such a size and distance

the perpetual ray; (those passing through portion

farthest removed from the centre) would as a result that rays from its extremities crossing in the eye

of this excess of curvature at the edges, focus sooner form a visual angle of not less than five minutes. than the more central rays; consequently light pro(5').

ceeding from a point would not reunite as a point, Angles are measured in accordance with what por

but as several points connected,--practically a linetion of a circle their sides would include ; for in

as the peripheral rays focusing closer to the lens

than all others and the remainder meeting slightly stance, every circle is composed of 360 degrees ;

farther back, as they pass through a more central if divided into four equal sections by lines point of the lens. This is termed Spherical Abberdrawn at right angles to each other through the ation, and in the early days of telescopes and microcentre, each of these sections would contain one

scopes was the despair of scientists and opticians for

years, as it practically prevented the use of lenses quarter of the whole circle, therefore -90°. If we

sufficiently strong or large to be of any service for subdivide one of these into ninety parts, each one the construction of powerful instruments. would be an angle of one degree, and wishing to In lenses such as are used for spectacles, there is still further reduce the size of the angle, we would

little inconvenience felt from Spherical Abberation,

they being too small and the curvature not great divide each one of the sections into sixty parts, each

enough to cause any optical defect. one of which would contain an angle, one sixtieth of

CHROMATIC ABBERATION. a degree-or one minute. Minutes being the subdivision of degrees, five of these latter would be the

Light upon being violently refracted, becomes de

composed into the various colored rays of which it is size of the visual angle necessary for clear vision.

composedas seen in the rainbow, which is the result of the strong light rays from the sun being vio

lently refracted by coming in contact with the rainAs has been already stated, the smallest image drops, which from their size and shape are very which the average human eye is capable of develop strong convex lenses. This phenomenon, which is ing into perfect vision must form an angle of five called Chromatic Abberation, while not entering into

consideration in spectacle lenses, was for a century or minutes at the nodal point.

more a positive barrier to all astronomical progress, In accordance with this established principle, test

as it rendered astrono'nical telescopes almost impostypes have been constructed with the letters of var sible, as we understand them to-day. It was finally ious sizes, each one of which if placed at the distance overcome by the invention of the Achromatic lens, which is indicated on the card will form an angle of

which instead of being composed of one piece of

glass, as was customary, was constructed on the plan five minutes. If we know that an eye possessing

of the human eye, being composed of several pieces, norinal vision can distinguish an object clearly

of different indices of refraction, cemented together. therefore read letters—which form an angle of not less than five minutes, and also possess a series of letters which we know will form an angle of exactly

THE OPTICAL QUERY. five minutes when placed a certain distance from the eye, we then have a positive rule of knowing the per

Subscribers wishing inquiries answered in this depirt. fect or imperfect condition of an eye by its ability or men! must send name and address, (not necessarily for non-ability to read letters forining this angle of 5".

publication.) The Snellens Test Type, such as is generally used,

Que-tions will be answered in the order in which they

are received. consist of several rows of letters of gradually decreas No attention will be paid in anonymous communica. ing size, each row being numbered to indicate the

sions distance at which it could be read.

To ensure a reply to questions relating to refraction By means of the Test Type, we readily measure

work a complete bistory of the case should be submitted the acuteness of vision, or degree of sight which an

J. C.-What instrument do you advise for opeye possesses and record it in the form of a vul

ticians as an assistant to the trial case. gar fraction, having for its numerator the distance at which the type is placed, and for the denominator consider

any of the much advertised machines for the number of the smallest line which it is possible eye testing take the place of the trial case ? to read; thus, if with the type twenty feet away an

Certainly no instrument can be said to supplant eye is able to read the line marked "20", vision would be normal and would be expressed 20:20; if

the place of the trial case. as it constitutes the the smallest line that could be read was inarked “60,Court of Appeal from all other methods of testing, the acuteness of vision would be 20, 60, or one third whether subjective or objective. Of what use


Do you

I suc

would it be to prescribe glasses of a certain strength

“AQUEOUS HUMOR." as indicated by instruinental test, if the patient states he cannot see with them?

A REMARKABLE CASE OF DIPLOPIA. I consider the retinoscope the most reliable in

A good story is told of an eminent Scotch divine, the results aimed at, as well as being the simplest who was noted no less for his eloquence than for of all objective inethods.

an occasional over-indulgence in his pet weakness In the February number of the Journal is puh- -the whiskey of his native land; upon which oc. lis ied a short sketch on retinoscopy, which should casions he lived in mortal dread of his better half, convey the information you desire.

who indulged in "curtain lectures ” G. W. M.-- i case of mixed astigmatism bothers Upon returning quite late one evening from some me, and I would be grateful for assistance.

public function at which his reverence had distinceeded in fitting the case, but am stuck in reduc- guished himselt by devotion to the "smoky ing it to proper focus.

Scotch," he ordered his serving man,—who was an R. V. 25/200. With +75 cyl, axis 40 C-2.50

old retainer and invariably accuinpanied him upon cyl axis 1.30=20/30, -20/40 withi +1.00 Sph=

these festive occasions for obvious reasons-to walk 20/20.

in the rear and clcsely observe his style of locomoThese suit nicely for distance, but for reading I tion and report whether it was advisable to go have to add +2 50 sph to bring the P. P. to 9 straight home or if the symptoms demanded “a inches. How can I get these all in one glass? walk around the block” before facing his observing Although the distant glass for right eye may

and “caddlesome" helpmeet. give good results it is impossible to grind it in its Old Davie sadly averred that he though it would present form as the axes of the two eyes must be

be advisable to “rin abit fairst." So forward they at right angles to each other, consequently it would

went in the “sma' hours of the night," the dominie read either +75 cyl axis. 40 = -2.50 cyl axis 130 keeping ahead at a smart pace and Davie in the or +75 C. axis 45 -2.50 cyl axis 135. Assum

wake, with inst:uctions to call a halt as soon as the ing the latter to be right, we could dispense with improved style of locomotion indicated that it one cyl by using -2.50 S. instead of

-2 50 C.

would be safe to return home. Up one street and This would correct the Myopic meridian in exactly

down another and still no word from Davie, until the same manner as a cylindrical would, but will at length the dominie exhausted asks impatiently make the hyperopic meridian just that much worse,

“What was wrong?” so that the cyl to correct it would be +3.25. The

“Hoot mon,” was the reply, “Ye're aw right correction would read -2.50 S. C +3.25 C. axis

yersel, but whu's that wi ye ?" 135. If we add +2.50 to this for reading, we have the -2.50 S. just neutralized by the +2 50 S.,

OPTICAL ALPHABET. which would leave for reading +3.25 cyl axis 135.

A for Astigmatism,-Corneal irregularity,

B for Blindness, --inability to see. “OPTICAL ALLUSION.”

C for Cataract,—an eye clouding trouble,

D for Diplopia, which means seeing double. The class just graduated from the Canadian Oph

E Emmetropia, the perfect seeing eye, thalmic College is a remarkable one, owing to the

F for Frame, which the lens is held by. number of representative dealers, who, realizing G for Glancoma, an eye hardening distress, that there is but one way to sell spectacles-the H Hyperopia, or far sightedness.

I riglit way--made arrangements to leave their busi- is for Iris, which is the eye's curtain,

J Jumping Headache, from eye strain,--that's ness long enough to get the necessary information.

certain. T'he class, though large, showed marked atten- K for Knowledge, which Opticians possess, tion, and passed a highly creditable examination. L is for Lens, which relieves the distress, During the closing exercises, the principal was M Myopia, or near sightedness,

N is for Nerves, which eye strain oppress. held up and presented with a tlattering address and

0 for Optician, who makes your eyes right, sɔmething substantial in the way of a remember

P Presbyopia, which means old age sight. ance from the class.

Q Quizzing,-a glass by dudes used, The following were

in attendance:-R. A. Ř for Retina, where the image is produced. Douglas, Barrie; H. E. Hurlburt, Tuornjury; G.

S for Strabismus, which means cross-eyed, W. Markle. Dindas; J. H. Stephenson, Markdale;

T is for Trial Case, with which vision is tried. W. M. Soit, Bradford; T. W. Turff, Truro. N. S. ; U is for Uniform, -- which both eyes should be.

V N. Neill. St. Thomas; G. Miller. Grimsby: F.

for Vision, which means -- just to see.

W Waste energy, caused by eye strain, Turner, Montreal, P. Qij P. Meunier, St.

X to 'Xamine and the cause ascertain. Johns, P. Q.; L. W. Nuole, London; W. H. Hewgill, Mouso.nin, Min.; D. C. Walterhouse, Turon- Y for Yourself-your eyes, -have them right

Z just Zealous we are for your sight. to.

[graphic][merged small][subsumed][subsumed][subsumed][merged small][merged small]

Established for the purpose of affording a thoroughly practical training in the science of optics and in

the ait of combining the various lenses to the correction of defective vision.



Diligence is the Price of our Diploma



the only Makers of Spectacles and Eye Glasses in CANADA.

We will hold a Class for Instruction in WINNIPEG, Man., Elementary Class commencing March 27th and closing April 8th, 1899. Advanced Class for Graduate Opticians, April 3rd to April 8th, 1899. Apply at once for Prospectus and Full Information.

Frame-Fitting and
Its Relation to Stock Keeping.

A Booklet, containing valuable suggestions on frame-fitting
and an original method of stock keeping, published by


the only Makers of Spectacles and Eye Glass in Canada.

At Cohen Bros.' suggestion, one of the most successful opticians in Canada adopted this system which the Booklet sets forth. He says: "Going back to the old system of handling frames would be almost like giving up the interchangeable system."

Every Optician in Canada is eutitled to a copy FREE.

[ocr errors]

The Practicability of Volumetric Testing for ious iron salts and solutions. Now prepare decinor-

mal potassium permanganate volumetric solution by

the second process, which gives good enough results BY JOSEPH FEIL, CLEVELAND.

and is not as intricate as the first proɔess; with this

test hydrogen peroxid, hypophosphites, etc. Finally For more than fifteen years volumetric tests of an unusually practical character have been a distin

prepare decinormal silver nitrate solution, and then guishing feature of the pharmacopeias of 1880 and

test chlorids, bromids, iodids, etc. 1890, and yet how rare is it to find a pharmacist who

The other volumetric test solutions of the pharmamakes actual use of these in his daily work? These

copæia may be tried if time is abundant, and the tests are preeminently practical and commercial and

work will be found interesting. Their preparation, require so little apparatus and time in actual use

however, is not really necsssary. that a very urgent cause must exist for this condi The time required to make a test after a solution tion of affairs.

is prepared is only a few minutes and the result a In seeking reasons from practicing pharmacists I necessity for the up-to-date pharmacist. As to cost, found that many seemed to think a high knowledge the only apparatus required, in addition to that of chemistry was an essential requisite to an under owned by every pharmacist, is a burette, a burette standing of the volumetric solutions, and, secondly, holder and a measuring flask, costing not over three that the processes were apparently intricate.

dollars, and, with care, lasting forever. As to the knowledge of chemistry required it may The chemicals needed, not usually found in drug be said that in many of the large chemical works in stores, would be about 2 ounces of chemically pure this country work of this nature is done hundreds of oxalic acid, the same quantity of chemically pure sotimes per day by men who are little more than or dium hyposulphte, and very small quantities, say oneninary laborers and who could not differentiate be

eighth ounce each or even less, of the important intween morphine sulfate and absorbent cotton, and dicators, such as phenolpthalein, methyl orange, the pharmacist accustomed to the preparation and

rosolic acid, etc., the total cost of chemicals being dispensing of drugs and galenicals can quickly attain

about 50c. I would recommend a pill tile as an exthe skill required if he desires to do so.

cellent base to place breakers or graduates on to The pharmacopeia is blamable for the idea of

note color changes and end reactions. Prof. J. U. complexity and intricacy in the operations indicated.

Lloyd has suggested to me the use of a capillary The alphabetical arrangement of volumetric solu

glass tube as an excellent method to note color tions seems at first sight eminently proper, but in changes; he says he has found that by the use of this particular case it is the cause of all the trouble.

this method duplicate tests can 'be made to exactly It happens that the two solutions heading the list

equal each other. The suggestion is well worth a are used with difficulty even by those who are ex trial. perts in this work, and, furthermore, having an ex

If a few pharmacists in the same town would meet ceeding limited application, they are the veriest

once a week or twice a month for two or three
terrors in practice and would hardly be missed,
though useful enough to the practicing chemist, but hours they could, with a little outside aid, or even
the pharmacopæia is not intended for chemists, but unaided, learn sufficient of volumetric quantitative
for pharmacists. The remainder of the solutions are analysis in six or eight lessons to be of great value in
easily prepared and still more easily used.

many directions.
If the following order is followed in the preparation
of these valuable adjuncts to the practicing pharma-
cist and the tests practiced on the substances nained,
the work will be one of pleasure and profit from

WHERE for "The Story nt the Philippines.”


by Murat Halstead, commissioned by the Governevery possible standpoint,

ment as Official Historian to the War Department. First prepare normal oxalic acid volumetric solu

The book was written in army camps at San Frantion ; from this prepare normal potassium hydroxid cisco, on the Pacific with General Merritt, in the solution, and then test various acids.

Next prepare

hospitals at Honolulu, in Hong Kong, the normal sulfuric acid solution with the aid of the

American trenches at Manilla, in the insurgent

camps with Aguinaldo, the deck of the potassium hydroxid solution and test ammonia

Olympia with Dewey, and in the roar of battle at water, salts of ammonium, lithium, sodium and the fall of Manilla. Bonanza for agents. Brimful potassium, such as carbonates, hydroxids, ignited of original pictures taken by government photog. organic acid salts with alkali metals, etc.

raphers on the spot. Large book.

Low prices. Next prepare decinormal sodium hyposulphite

Big profits. Freight paid. Credit given. · Drop

all trashy unofficial war books. Outtit free. Advolumetric solution and with the test tinctures of

dress H. L. Barber, Gen. Manager, 356 Dearborn jodin and of įron chlorid, calcium chlorid and var Street, Chicago.


« AnteriorContinuar »