The Electricity Laboratory has indeed achieved remarkable results in the past five years, but whether it is the electric motor or the carbon filament light bulb, the related theories were proposed by Carlo.

This makes Graham deeply admire Carlo, even considering him a born scientist. If he hadn’t become the King of Spain, Carlo would definitely have become one of the greatest scientists in human history, perhaps achieving greatness comparable to being a king.

Unfortunately, having become the King of Spain, Carlo clearly doesn’t have much energy to devote to scientific research and development, which makes Graham, who admires Carlo greatly, feel regretful, believing that humanity may have missed out on a great scientist.

Upon hearing Graham’s introduction, Carlo nodded with a smile and asked his question: "Mr. Graham, can the lifespan of this carbon filament light bulb currently be guaranteed to exceed 300 hours?"

A lifespan of 300 hours is certainly short for future light bulbs, but for this era’s light bulbs, it represents a significant improvement.

For ordinary households, it’s not possible for the electric lights to stay on all night; the basic lighting time for a night is just the first few hours after it gets dark.

Calculating at 3 to 4 hours of lighting per day, this kind of carbon filament light bulb’s lifespan will last about 75 to 100 days, which is roughly three months.

Even for streetlights that illuminate throughout the night, calculating at least ten hours of lighting per day, a 300-hour lifespan can still be used for more than ten days.

This era is not like future generations, where many roads would have streetlights. Even if Spain has a demand for constructing streetlights, it would only be on certain more bustling streets and within cities; ordinary roads should not even be considered.

Considering all of this, although a lifespan of 300 hours is not long, it is definitely sufficient for commercial use. As long as the production cost of the light bulbs is not high, these light bulbs can be fully commercialized, and through this, promote the use of electricity. This is also the reason Carlo is concerned about the lifespan of these carbon filament light bulbs.

"We have manufactured hundreds of these carbon filament light bulbs, among which the lifespan of over 60 exceeds 400 hours, nearly 20 exceed 350 hours, and only less than 20 barely maintain around 300 hours."

Your Majesty, based on these experimental results, we are confident that the lifespan of the carbon filament light bulb can be maintained above 300 hours, and it may even be possible to increase it to over 350 hours in a short time." Graham, mentioning the actual lifespan of the carbon filament light bulb, responded enthusiastically to Carlo’s question.

Compared to the current research and registered patents on light bulbs in various countries, Spain’s light bulb, with a minimum lifespan of up to 300 hours, is undoubtedly quite advanced.

To personally accomplish such a feat, for Graham, who loves scientific research, is more wonderful, exciting, and thrilling than anything else.

Carlo nodded, the smile on his face growing wider.

In this view, Graham’s reported lifespan of 300 hours for the light bulbs is actually quite conservative.

Because the majority of the light bulbs have a lifespan exceeding 400 hours, with some inferior ones only having a lifespan of 350 or 300 hours.

According to some capitalist exaggerations, these carbon filament light bulbs could be advertised as having an average lifespan of over 400 hours, with the highest lifespan nearing 500 hours, presenting exaggerated results.

Graham did not do this, also proving his meticulousness with the experimental data.

"Light a few light bulbs," Carlo instructed.

Regarding these most primitive electric lamps, Carlo was quite curious. Although Carlo had also experienced those dim incandescent lamps, these products had been improved many times over a century later.

And what these most primitive incandescent lamps over 100 years ago look like and the brightness of the electric lights are things Carlo does not know now.

Upon hearing Carlo’s instructions, Graham signaled his assistant to turn on the switch.

With a click of the switch, several light bulbs on the laboratory table instantly lit up. Because it was daytime, the brightness of the light bulbs was not high; it could even be said to be very faint.

Carlo frowned, realizing that conducting light bulb tests during the day was not a wise choice.

Fortunately, the Electricity Laboratory had a way to handle it. All the windows were fitted with curtains, and the lighting areas were shut down, making the laboratory completely dim.

Having a darkened laboratory as a backdrop, the originally dim light bulbs suddenly became bright. Although they weren’t as dazzling as the lights of future generations, for the initial development of electricity in 1875, such lights seemed like a spark on the prairie, ready to catch the wind and trigger a widespread fire.

Feeling the brightness of the light bulbs, Carlo nodded, quite satisfied in his heart.

Afterwards, the light bulbs were turned off, and several kerosene lamps lit up again.

This time the contrast was even more obvious. Although the brightness of the previous light bulbs wasn’t very high, it was absolutely clearer than kerosene lamps.

If only judging by brightness, the brightness of such light bulbs was at least several times that of kerosene lamps, looking at things much more clearly. 𝗳𝐫𝚎𝗲𝚠𝚎𝗯𝕟𝐨𝘃𝚎𝗹.𝗰𝗼𝗺

Working in an environment lit by light bulbs, at least it wasn’t as harmful to the eyes as kerosene lamps. With such a comparison, Carlo was even more satisfied with the current light bulbs.

"Your Majesty, what you see is the small light bulb we have manufactured, mainly intended for civilian use lighting.