Headgear
The Glengarry.
According to its Wikipedia entry, the Glengarry was made part of the uniform of the Glengarry Fencibles by Alasdair Ranaldson MacDonell of Glengarry when they were formed in 1794 and he was described as having invented the cap. However, as worn by Scottish Highland regiments the original voluminous blue bonnet gradually developed into a stiffened felt cylinder, often decorated with ostrich plumes sweeping over the crown from left to right (as well as flashes of bearskin or painted turkey hackles). In the 19th century this tall cap evolved into the extravagant full dress 'feather bonnet' while, as an undress cap, the plainer form continued in use until the mid-19th century. By then known as the 'Kilmarnock' bonnet, it was officially replaced by the Glengarry bonnet, which had been in use unofficially since the late eighteenth century and was essentially a folding version of the cylindrical military cap.
It is interesting that the three Victorian illustrations below show approximations of all three stages of the Balmoral's supposed conversion to the Glengarry. Hopefully a military hat historian will leap to our rescue!
The three hats shown here are contemporaneous. This first one appears to be the Balmoral . . . 
. . . which becomes shaped like an inverted pudding basin and is no doubt the 'Kilmarnock' which . . . . 
. . . when dented in the middle begins to look suspiciously like a Glengarry.
Capable of being folded flat the Glengarry became a characteristic part of the uniform of the Scottish regiments where it was worn in various guises.
During World War II it was always worn by the Forces at a very jaunty angle and know as the forage cap: the right side of the cap was worn low, often touching the ear, and the side with the cap badge higher on the head. The trend since the end of the war has been to wear the Glengarry level on the head.
Nowadays it's commonly worn by civilians, notably civilian pipe bands, but can be considered an appropriate hat worn by any males with Highland casual or evening dress.
Also known as the side cap, was the RAF forage cap an adaption of the Glengarry? 
A Canadian Glengarry style military hat.
The Balmoral
The Balmoral bonnet dates back to at least the 16th century when it was a soft, knitted wool cap with a voluminous, flat crown, traditionally blue in colour, sometimes with a diced band (usually red-and-white check) around the lower edge and with a coloured toorie (pom-pom) set in the middle of the crown.
The forefather of the Balmoral bonnet? The Tam o' Shanter makes a comeback. Photo Burns Bunnet Co.
The name 'Balmoral' as applied to this traditional head dress appears to date from the late 19th century. Today, the crown of the bonnet is smaller, made of finer cloth and tends to be blue or Lovat green. Tapes in the band originally used to secure the bonnet tightly are sometimes worn hanging from the back of the cap. It can have a regimental or clan badge worn on the left hand side with the bonnet usually worn tilted to the right to display these emblems. The Balmoral was adapted into the Caubeen by Irish Forces and military forces around the world have worn it and referred to it simply as a 'beret.'
The Black Watch Balmoral beret. 
Canadian Military Balmoral beret 
HRH Prince Charles wearing the Red Beret
Naval cadets
The Chiefs
We've spoken of the chiefs' eagles feathers before and it might be of interest to discover 
that they - and the Chieftains and Armigers - are at risk from some of Britain's most draconian laws. That law is concerned with the protection of widlife and eagles are included in the legislation. The law lays the onus on the owner of the feathers to prove his innocence rather than the prosecutor having to prove his guilt! Chiefs and chieftains now consider it wise to have a letter from someone authorised to keep eagles in captivity, or a licensed taxidermist, stating that the bonnet feathers come from a legitimate source. Although Britain's wild eagles cast more than 30,000 tail and wing feathers during their annual moult - all of them blowing about on hill and moor -- no allowance was made for this by the law-makers and it is assumed 
that if the armiger is in possession of an eagle feather, he killed the bird to get it!
.jpg "Balmoral black with diced band. Photo Kinloch Anderson.")
.jpg "Plain Balmoral in Lovat green. Photo Kinloch Anderson.")
