This 52 inch penny farthing was built by the firm of Jos. R.A. Hoyer, based in Tetschen. That town is now called Děčín in Czech. Saddle and pedals are later replicas and the bike has been restored. It is a nice bicycle, I guess built in the years 1885-1888. Hollow front forks, semi-hollow rear fork. Detachable handlebars of a unique construction, I guess a Hoyer patent?
Front ball bearings are the well known Bown Aeolus model.
The spring is the beautiful Humber type that we see a lot on ordinaries from the 1884-1889 period.
I'm afraid I have no further information about Hoyer. Who helps me out?
The pictures come from Max, look at his nice blog at www.veliciousbicycles.com where he takes this beauty out for a ride in Austria.