Found Online: Vogue, 1910-1919.

 Some generous soul (or more likely, institution) has put the complete run of Vogue  from 1910 to 1919 online at the Internet Archive.  That takes us all the way from the last Edwardians to the first flappers!

In 1909 Conde Nast bought an ailing weekly called Vogue, dedicated to recording the doings of high society (and their clothes).  Nast took this uninspiring magazine, gave it a new look, issued it fortnightly instead of weekly, added a dash of arts and news reporting, and expanded its readership.  In short, he turned it into the Vogue we know today (though fashion and Society remained at its core).

So let us take a look at the women of the 1910s and their fashions as seen in Vogue.  Hang onto your hats, gentle readers, because this is going to a helluva long ride. 

1st April 1910

First, 1910.  Hats were huge:

And most of them are huge, these new hats! Their brims sweep wide; their square crowns are prominent, when they are not quite hidden under the loads of flowers and feathers. On these latest hats waving ostrich feathers are supplanting aigrettes and skeleton feathers. 
(15th January, 1910)

Collars were loosening: 

More and more the neck is loosed from the longtime thraldom of stiff binding collars and boned tortures... The fancy quite accepted, it is no uncommon thing to see in fashionable tea rooms, at five o’clock, women, with neck piece and coat thrown back, showing throats uncovered an inch or two, sometimes more, below the base of the throat.
(5^th February 1910)

(An "inch or two" of throat was quite daring in 1910!)

Skirts, however, were decidedly straight and narrow:

Lines continue straight, skirts being narrow and scant of material, though there is a tendency to soften rigid outlines by the use of draperies and sashes. 
(15 October 1910)

... Which necessitated some fashion innovations:

The prospective débutante must provide herself with black and white satin knickerbockers, lined with albatross, in lieu of petticoats in these days of narrow skirts.
(1^st November 1910)

and

The vogue of the narrow skirts, however, has brought about a greater attention to the style of shoes and stockings, and there is no telling where we may arrive; for the most daring novelties are being adopted abroad, and eventually may be welcomed here. 
(15 November 1910)

15th June, 1911

Hats were still wide, skirts still narrow, and waistlines were rising in 1911.  However the fashion news that shocked everyone in 1911 was the introduction of the Jupe Culotte, also know as the Harem Skirt: 

A few extremists are essaying the trouser dresses, and practically all the exclusive as well as our larger emporiums are showing what they are pleased to term harem models.

As a matter of fact, the majority of these, destined for street wear, bear no sort of resemblance to the native harem trouser dress, and merely comprise a straight hobble skirt, more severely hobbled by being either stitched up a short distance from the hem in the centre, or with the back and front of the skirt caught together in the centre, and seamed horizontally, thus forming an aperture at either side for the feet to pass through. 
(15^th April 1911)

Judging by Vogue's advertising pages, few, if any, women wore these fashions. 

15th July, 1912

Browsing through the 1912 issues of Vogue, I got the impression that girlish simplicity was the theme of the year. 

Everywhere flowers, except on the hats. There we see only aigrettes and feathers. The hat may be large or small, have a wide brim or no brim at all, but always it displays an aigrette. This may stand up in front as stiff and straight as a Georgia pine, be posed slantindicularly across the crown, lie flat on the brim, or hang practically by a thread, but it always looks smart and gives just the proper touch to either tailor-made or fussy frock. 
(1^st July 1912)

Drapery. There is no drapery below the knee, but above the knee, what variety! Plaited peplums, puffed peplums, short tunics made of double frills, puffed tunics, circular tunics, godets, elongated, split panniers, and, most striking of all, very puffy panniers…
(15^th October 1912)

1st November, 1913

"Uncorseted" was a favourite adjective in 1913.  Oddly enough, it appeared most often in advertisements for corsets!

VERY GENTLY, VERY GRADUALLY, THE COUTURIERS ENTICE US TO THE NEW, SNUG-FITTED SILHOUETTE, THE WHILE THEY KEEP AN EYE TO WINDWARD BY SHOWING MODELS AS UNCORSETED AS IN THE SEASONS PAST—THE BURDEN OF CHOICE RESTS WITH US
(1^st April 1913)

1st April, 1914

In August 1914, war broke out in Europe.  Vogue, however, had its own priorities. 

During the first days after the declaration of war, while mobilization was taking place, fashion prospects were thunderous. No one cast them a thought. Many of the creators of fashion immediately joined their regiments. Paul Poiret and Jean and Jacques Worth were among the first to go. When the head of the house was not away on affairs of war, his assistants were; his designers were enlisting; his little sewing girls were with the Red Cross or he had set them to work in his ateliers making bandages; his vendeuses were with their families, helping in the preparations for war; approached on business, they could only weep.

But after the first upheaval, many of the houses, notably those headed ‘by women, were able to resume their normal activities,—even to hold their openings on the days scheduled. The trade of France must not too greatly suffer…
(1^st September 1914)

1st July, 1915

Shades of the 1920s in this little item from 1915:

Mrs. Castle, who certainly has a marvelous flair for personal effectiveness, did the newest thing in coiffures when she bobbed her hair. This is such a radical departure from the usual, and would be so hard to wear in the majority of cases, that there is little likelihood of its general adoption.
(1^st February 1915)

"Mrs Castle" was Irene Castle, the famous dancer and fashion trendsetter.

Just at present the Parisienne affects the greatest sobriety in dress. Tailored frocks of puritanical simplicity are all that one sees in the streets and tea-rooms, or at the matinées. Evening performances there are none, as yet, and as the restaurants are obliged to close at an early hour, not much attention has been paid, so far, to dinner or evening gowns.
(15^th February 1915)

Though America had yet to join the war, the writers at Vogue were of course very attuned to what was happening in Paris.

15th October 1916

Vogue went international in 1916, with the start of its British edition.  Meanwhile, in the same year, one of the great designers of the 20th century began to make her mark. 

Chanel, always devoted to jersey, continues to make stunning garments of that rather hard-worked fabric. It has been rumored lately that women were growing tired of jersey, but Chanel is master of her art, and her jersey frocks are as complete and as daintily finished as frocks of more thoroughly patrician stuffs. 
(1^st November 1916)

Simple styles in simple materials that were perfectly in step with the times.

1st April 1917

The United States entered the war in April 1917, but the fashionable world was already feeling war's effects before then.  The world's wool supplies were being used up for soldiers' uniforms, and the best and brightest dyes, previously made in Germany, were no longer available.

The war is responsible for so many things,— for the new narrow skirts, for the color of our frocks, for the shape of our hats, and for the texture (and price) of our gloves and shoes; to the war is due, also, the great cost of woolen stuffs and the resulting popularity of silks and satins. Owing to the war, sports coats—the milder variety, of course—are made of satin instead of cheviot, and in order to economize, one orders a frock of silk instead of a frock of serge. 
(1^st March 1917)

There is nothing especially new about the straight frock, but the straight frock is one we all love. Comfortable, graceful, and generally jolly is the straight frock, concealing in kindly fashion so many physical shortcomings. Its loose belt vaguely outlines the waist; its easy skirt skilfully veils alike the too-stout and the too-slight figure. Not that one can really be too slight in these latter days when slenderness is absolutely imperative.
(15^th March 1917)

1st May 1918

One gets the impression that Vogue's Paris correspondents were struggling after four years of war. 

PARIS SMILES THROUGH WARTIME SACRIFICES
In the afternoons, we meet each other a great deal, no matter where we are, for bridge and music. As we have neither autos nor carriages (for the prices of these vehicles are prohibitive at the watering-places), the most fastidious women have remained true to the informal costume, consisting of a blouse and skirt with a woollen or silk sweater, a simple frock of jersey, or one of piqué for very warm days. A few strangers dress for dinner at the hotels…
(15^th July 1918)

15th May, 1919

And so we come to 1919, and peaceful times again.

We have awaited disaster with calmness in the past, but we await the fruition of peace with a natural impatience. There are so many things we want to do; factories to start again; designers to bring back from the trenches and into the ateliers; nimble-fingered workwomen to beguile from the higher wages of the munition plants to ply their own lovely trade again.
(1^st January 1919)

War had left its mark in a trend for more practical fashions (at least for the class of women that wore tea gowns!)

 WAR and war-time conservations have had their effect on tea-gowns and other types of house gowns, quite as much as on the other garments in the feminine wardrobe. The most,noticeable result has been to make them a great deal more practical and, as a rule, really warm, instead of mere wisps of dainty chiffon trimmed with lace. 
(1^st January 1919)

Blouses—even lacy, frilly ones—were also practical.  They didn't take much material to make, could be paired with different skirts, and best of all, could be washed.

 THE popularity of the blouse fluctuates more than that of any other article of feminine attire. Just at the moment it is on the upward wave and, strangely enough, it is the essentially feminine variety of blouse—the lacy, frilly, washable affair—that is making the strongest bid for favour.
(1^st January 1919)

 Not everything was practical, however.  The Jazz Age was getting off to a start, and women wanted something gorgeous to party in.

Evening gowns have abandoned war-time simplicity in favour of sumptuous fabrics such as rich gold and silver tissues. ‘Taffeta, faille, and black, white, and coloured brocades are all shown. Trimming is sparsely used, but when it does appear it is rich and unusual.
(15^th Jan 1919)

 There was a confusion of styles, as designers struggled to find a postwar look.  One thing was certain: long skirts and corsets were not going to make a comeback.

 The first question to be asked by the woman who could not go to Paris herself is “What is the new silhouette”? ‘The “new silhouette,” as it has been exemplified by the collections, is so varied and so individual that it is impossible to speak of it in the singular...

Rather more fitted bodice lines are a feature of many of the new modes. This was inevitable when the pannier or hoop skirt was introduced, and nearly all the collections have followed the dictates of reason in wrapping the waist rather more snugly. There is but little indication of the tightened waist-line, however, and none at all of the corseted figure. Every manikin in every house showed the models without corsets. 
(15^th October 1919)

The skirt suit seems to have been a "practical" (that word again!) favourite.

SURPRISINGLY enough, several of the leading Paris houses, working independently of each other, have decided to revive for this winter the contrasting blouse with the tailored suit, instead of the dress and coat combination which has been more in favour in recent seasons. ‘This fashion of amusing or elaborate blouses, quite different in colour scheme and material from the suit for which they are designed, is a very practical one for the woman whose wardrobe requirements outrun her income, or at least come close enough to doing so to cause her some anxiety.
(15^th November 1919)