7 May
The Superb, one of the few remaining unconverted sail liners of the Royal Navy, is taken into Chatham for modification. In addition to recieving an auxiliary engine, she will be stripped of many of her guns and converted to a mortar ship for the mammoth 36" Mallet's Mortar, a weapon capable of firing one-ton shells. She will also be supplied with compartments to carry replacement sections for the mortar (which is modular and can have broken parts swapped out for new).
Pisces and Capricorn reach the Detroit river and begin to sail up, with the gunboat Ripple going ahead. Ripple comes under fire from a Union battery on the shore, and returns fire - soon being assisted by the heavy rifles of Pisces firing at a range of 300 yards.
The battery is quickly neutralized, and the surviving gunners ride west - they were intended more as a delaying action than anything.
The Union Army of the Detroit is pulling back from the Canadian border, choosing to fall back into the western section of the Lower Peninsula in order to avoid being encircled and destroyed. Grand Rapids is considered far enough from the border that the British-Canadian attackers cannot easily reach it without setting up new logistics lines, and Blair sends sulfurous telegrams southeast demanding reinforcement. (One of the phrases he uses is "due to the great peril of the region in a military sense compared to the inactivity elsewhere", a deliberate twisting of the words used to get him to give up troops two weeks ago.)
Unfortunately for him, there are relatively few options. Taking troops from the Army of the Potomac is simply impossible due to the Confederate presence in Maryland and DC, Kentucky barely has the troops to keep Johnston in check, and removing troops facing the British in the Northeast is considered unacceptably risky. (The Niagara frontier has already suffered a serious reverse and has no surplus troops to give, the army near the St Lawrence was raided for troops only a few days ago and there are worries that a further drawdown on the eastern coast would cause other mayors and governors to contemplate Wood's hinted-at plan.)
As such, the reinforcements Blair demands are to be taken from Missouri - the one area things seem reasonably under control. 20,000 troops are detached from this army and begin the laborious process of railing north.
8 May
The Great Eastern undocks from Pembroke, modified for war service. She now mounts twenty 8" shell guns and a dozen 110-lber Armstrong guns along her sides, with strengthening to assist her frame in taking the recoil of these weapons, and has been outfitted to carry military stores.
In this configuration, she can carry three battalions complete with stores, artillery and ammunition, along with large quantities of supplies. Her first run will be to take replacments across to Canada, carrying three thousand troops plus 9,000 tons of supplies at an average passage speed of 14 knots.
The reason for her radical up-arming is that she is considered to be too valuable a target for commerce raiders to go unprotected.
A raiding force (three British battalions and 5,000 Canadian militia, ferried in lakes shipping and supported by the Scorpio) attacks Cleveland, Ohio. The raid sinks those local armed ships which do not flee, overwhelms the few defending troops (a couple of thousand infantry, poorly armed), destroys or captures the ships undergoing conversion into armed vessels, and troops destroy the railroads for several miles around Cleveland in both directions.
When combined with Confederate advances in Maryland, this in fact limits the entirety of the rail traffic to the western Union to one rail line passing through Pittsburgh. Logistic bottlenecks result, making it even harder for the Union to manage their limited resources.
At about the same time, Pennefather discovers the American withdrawal from the Detroit. He begins making preparations for a general advance, leaving around one third of his force to garrison the river line - capturing Detroit will be very prestigous, and as it is an important industrial city will have deleterious effects on the Union.
A small skirmish takes place some miles outside San Francisco between Union infantry (effectively mounted infantry due to their use of horses to get around) and a platoon of Gurkhas. The Gurkha infantry are using the Brunswick rifle, not the Enfield (this is deliberate policy after the Indian Mutiny; less reliable troops are given the .656 smoothbore, though none of those are in the California expedition) and deliver a terrifying Kukri charge which routs the Union platoon.